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Published byEIROforum:

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ISSN:1818-0353

Subscribe (free in Europe): www.scienceinschool.org Highlighting the best in science teaching and research

In this issue:

Biomimetics:clingy as an octopus orslick as a lotus leaf?

Also:

News from the EIROs:

Mars, snakes,robots and DNA

How many schools

do you reach –

worldwide?and teachers

Advertising in Science in School· Choose between advertising in the quarterly print journal or on our website.· Website: reach over 30 000 science educators worldwide – every month.· In print: target up to 15 000 European science educators every quarter, including

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Spring 2011 Issue 18

This issue of Science in School is rather special: it’s nowfive years since Science in School was launched, in

March 2006.

During the past five years we have published 350 articles, ontopics ranging from particle physics and astronomy, via cli-mate change, earthquakes and spectrometry, to evolution,biodiversity and diabetes. Many of those articles have beentranslated for publication on our website – producing a fur-

ther 788 articles in 28 European languages.

Likewise, our readership continues to grow and grow: about 15 000 copies of theEnglish-language print journal are distributed across 41 European countries, andour website receives well over 30 000 visitors from across the world every month– a figure that continues to rise. Science in School is read not only by teachers,but also by teacher trainers, scientists and many others who are interested in science education.

Perhaps you, as one of our readers, have wondered who is behind Science inSchool? Who makes it possible for science educators across the world to shareinspiring teaching ideas or keep up-to-date with cutting-edge science – for free?

First, there are the publishers of Science in School: the eight European inter-gov-ernmental research organisations that make up EIROforum (see page 2). The ideafor the journal was born of EIROforum’s commitment to supporting and improv-ing science education in Europe, and EIROforum has funded the journal rightfrom the beginning. From 2005 to 2008, there was also generous support fromthe European Commission.

Francesco Romanelli, current chairman of EIROforum, explains: “EIROforumrecognises the importance of science education, both to train the next generationof scientists and to ensure a scientifically literate public. Teachers are a vital ele-ment in this process, and we are proud and happy to support them with Sciencein School.”

On a day-to-day level, the journal is run by a two-person editorial team. Beforemoving into publishing, both my colleague Dr Marlene Rau and I spent severalyears in research: Marlene in developmental biology, and I in insect ecology. Wesource, edit and sometimes write the articles; organise the copy-editing, layout,printing, distribution and translation; maintain the website; publicise the journal;sell advertisements and generally keep everything running. It’s a lot of work butenormous fun.

Of course, none of this would be possible without a great deal of voluntary help.We currently have 76 referees – European science teachers who help us decidewhich articles to publish and how they could be improved. More than 250 scien-tists and teachers have volunteered to translate articles into languages fromAlbanian and German to Portuguese and Ukrainian. And of course there are theauthors, who share their teaching ideas and scientific knowledge with our readers.

We would like to extend our grateful thanks to these people and to everyone elseinvolved. We look forward to the next five years of Science in School!

Eleanor HayesEditor-in-Chief of Science in [email protected]

About Science in SchoolScience in School promotes inspiring science teaching by encouraging communication betweenteachers, scientists and everyone else involved inEuropean science education.The journal addresses science teaching both acrossEurope and across disciplines: highlighting the best in teaching and cutting-edge research. It covers not only biology, physics and chemistry, but also earth sciences, engineering and medicine,focusing on interdisciplinary work. The contents include teaching materials; cutting-edge science; interviews with young scientists and inspiring teachers; reviews of books and other resources; andEuropean events for teachers and schools.Science in School is published quarterly, both onlineand in print. The website is freely available, with articles in many European languages. The English- language print version is distributed free of charge within Europe.

Contact usDr Eleanor Hayes / Dr Marlene RauScience in SchoolEuropean Molecular Biology LaboratoryMeyerhofstrasse 169117 [email protected]

SubscriptionsRegister online to:

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SubmissionsWe welcome articles submitted by scientists, teachersand others interested in European science education.See the author guidelines on our website.

Referee panelBefore publication, Science in School articles arereviewed by European science teachers to check thatthey are suitable for publication. If you would like tojoin our panel of referees, please read the guidelineson our website.

Book reviewersIf you teach science in Europe and would like toreview books or other resources for Science inSchool, please read the guidelines on our website.

TranslatorsWe offer articles online in many European languages.If you would like to volunteer to translate articles intoyour own language, please read the guidelines fortranslators on our website.

Advertising in Science in School –new lower pricesScience in School is the only European journal aimedat secondary-school science teachers across Europeand across the full spectrum of sciences. It is freelyavailable online, and 15 000 full-colour printedcopies are distributed each quarter.The readership of Science in School includes everyoneinvolved in European science teaching, including:

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Editorial

Happy birthday, Science in School!

sis_18_RZ_.qxq:Layout 1 15.03.2011 18:08 Uhr Seite B

Science in School Issue 18 : Spring 2011 11

Contents

17

EditorialWelcome to the eighteenth issue of Science in School

News from the EIROs2 Mars, snakes, robots and DNA

Events6 Science on Stage: countdown to the international festival

10 Young scientists at the cutting edge: EIROforum prize winners13 Young minds in science: the European Union Contest

for Young Scientists 2010

Feature article17 Battle of the birds: interview with Tim Birkhead

Cutting-edge science21 Moringa: the science behind the miracle tree27 Uracil in DNA: error or signal?32 A neural switch for fear

Teaching activities36 The resourceful physics teacher40 Breeding dragons: investigating Mendelian inheritance

Science education projects46 The heat is on: heating food and drinks with chemical energy52 Biomimetics: clingy as an octopus or slick as a lotus leaf?

Science topics60 Single molecules under the microscope

Additional online materialTeacher profileTeacher solidarity: a UK-Rwandan physics project

Scientist profileTo sea with a blind scientist

ReviewsBad ScienceInstructables websiteRelativity: A Very Short Introduction

Forthcoming events for schools: www.scienceinschool.org/events

See: www.scienceinschool.org/2010/issue18

At the end of each article in this issue, you may notice a square black and whitepattern. With the aid of a smart phone, this QR code will lead you straight to theonline version of the article. All you need to do is download a free QR code readerapp (such as BeeTagg or i-Nigma) for your smart phone and scan the code withyour phone’s camera. To find a suitable one for your phone, see:http://tinyurl.com/byk4wgHint: the apps works better in good light conditions, and with a steady hand. Youmay also want to try holding your camera at different distances from the code.

You can then use all the live links to the references and resources, download the PDF, send thearticle to your friends, leave comments, and much more. What do you think about this new fea-ture? Does it work for you? Leave your feedback here: www.scienceinschool.org/QRfeedback

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www.scienceinschool.orgScience in School Issue 18 : Spring 20112

EIROforum, the publisher of Science in School, is a partnership of eight European inter-governmental scientific research organisations (EIROs). As regular readers of Science in School will know, the range ofresearch done at these organisations varies widely – frommolecular biology to astronomy, from fusion energy tospace science. The equipment is also very disparate –

including enormous particle accelerators; beams of neutrons or high-energy X-rays; large telescopes or the International Space Station.

Whether individually or as part of EIROforum, the EIROs are also involved in many outreach and education activities – for school students, teachers or the general public. Science in School is one example of a joint EIROforum activity; this article details some of the other research and outreach activities of the EIROs.

For a list of EIROforum-related articles in Science in School, see:www.scienceinschool.org/eiroforum

To learn more about EIROforum, see: www.eiroforum.org

Juliette Davenne (left) and Marie Bugnon(centre) from CERN’s communicationgroup prepare the mystery boxes for primary schools with Olivier Gaumer(right) of PhysiScope

CERN: young scientists in the makingWith help from CERN, some 700 Swiss primary-school children from

the Geneva area will try out the scientific method for themselves thisyear. On 26 January 2011, 30 local primary-school teachers met at thesite of the LHCb experiment for the launch of the ‘Dans la peau d’unchercheur’ (‘Be a scientist for a day’) project, a joint activity by CERN,PhysiScope (University of Geneva) and the local education authorities in

the Pays de Gex and the Canton of Geneva.From February to June 2011, children aged 9-12 will carry out their own investigations

to try to discover what is inside a mystery box, just like CERN scientists attempting todetect particles which cannot be seen with the naked eye.

The pupils will begin by designing and carrying out experiments, after which they cancompare their ideas and send questions to CERN scientists via the project website. In Apriland May, they even get to visit a CERN experiment or take part in a PhysiScope event – achance to grill the physicists about their own experimental methods. Finally, the childrenwill give a lecture of their own, just like real scientists do.

For more information, visit the website (in French): www.cern.ch/danslapeaudunchercheurFor more ideas for teaching about black boxes, see:

www.scienceinschool.org/advent2010/day1For a list of CERN-related articles in Science in School, see: www.scienceinschool.org/cernTo learn more about CERN, see: www.cern.ch

Mars, snakes robots and DNA

Image

courtesyof C

ERN

Image courtesy of CERN


News from the EIROs

www.scienceinschool.org 3Science in School Issue 18 : Spring 2011

EMBL: the first annual schools lectureOn 10 December 2010, Dr Jan Korbel addressed 150 school

students and their teachers at the European Molecular BiologyLaboratory (EMBL) in Heidelberg, Germany. Several hundredmore watched live over the Internet from classrooms acrossEurope. In the first in a series of annual EMBL Insight Lectures,Jan described the advances that have recently been made inDNA sequencing technology and human genome analysis, andthe possible implications that these advances could have for dis-ease research – particularly cancer research. Questions camefrom both the lecture hall and classrooms via Skype.

“As scientists we have anobligation to explain ourresearch to the public, whichobviously includes the youngpublic who are still undecidedabout their career path,” says Jan. Philipp Gebhardt, educationofficer at the European Learning Laboratory for the LifeSciences, EMBL’s education facility, which organised the lecture,points to the value of communicating science in such a way:“There is a great social aspect to this. Many people in differentcountries can watch the same lecture at the same time and askquestions directly to the speaker. It makes it accessible to every-one.”

The lecture remains accessible, as it can be watched here:www.embl.org/ells/insightlectures

For a list of EMBL-related articles in Science in School, see:www.scienceinschool.org/embl

To learn more about EMBL, see: www.embl.org

EFDA-JET: fusion energy for schoolsFusion holds many attractions for school students of all ages –

the concepts of atoms, the Sun and clean energy resonate just asmuch with 5-year-olds as with pre-university students. Cateringfor this range has led the communications group at Culham, UK,to develop different tools: on-site visits and off-site talks for theolder children and school visits with the ‘Sun Dome’ – a sort ofmobile planetarium – to engage the younger children.

Visits to EFDA-JETare very popular. Some1500 school studentsvisited in 2010 and somany schools want to

visit (and revisit) that bookings are now being made for 2012.Over the past 18 months, visiting school classes have had theadditional excitement of getting a glimpse of the actual fusionreactor (JET), which is being refurbished. When it is operating,the reactor is of course sealed off for safety reasons. Even then,however, visitors can see a full-scale model; this shows the interi-or of the reactor and the robotic arms that carry out most of thework inside (see image).

Education manager Jo Silva is delighted that so many studentsare learning about fusion: “It’s fantastic to see this enthusiasmthat hopefully will translate into a new generation of scientistsand informed public.”

To learn more about EFDA-JET, see: www.jet.efda.org

For a list of Science in School articles related to EFDA-JET, see:www.scienceinschool.org/efdajet

Robotic arm insidethe JET fusion

reactor

Science in School is published by EIROforum, a collaboration ofresearch organisations. Eleanor Hayes, Editor-in-Chief of Science inSchool, reviews some of the latest news from the EIROforum members.

Image

courtesyofEFD

A-JET

Image

courtesyofAndré-PierreOlivierandJanKorbel

Image courtesy of EM

BL Photolab


www.scienceinschool.org

ESA: walking on ‘Mars’The first humans have landed

on ‘Mars’! On 14 February 2011,Italian Diego Urbina, RussianAlexandr Smoleevskiy and Chinese

Wang Yue took their first steps on the simulated Martian surface.The sandy 60 m2 terrain, designed to resemble the Gusev crater onthe Red Planet, is housed in the Institute of Biomedical Problemsin Moscow, Russia, one storey above the cylindrical modules hous-ing the crew.

“Today, looking at this red landscape, I can feel how inspiring itwill be to [be] the first human to step foot on Mars,” said Diego atthe beginning of his three-hour ‘Mars-walk’ with Alexandr.

This was the highlight of the first full-duration simulated flight toMars, the international Mars500 project with extensive participa-tion by the European Space Agency (ESA). For more than eightmonths, Diego, Alexandr and Yue and three colleagues had beenisolated on a virtual ‘flight to Mars’.

Once the mothership arrived in ‘orbit’ around Mars, Diego,Alexandr and Yue entered the lander on 8 February 2011 and‘landed’ on Mars four days later. After three Mars-walks, theyreturned to the mothership on 24 February, rejoining their col-leagues who had continued to orbit Mars.

Finally, on 1 March 2011, the most difficult part of this psycho-logical study of long flights began: another eight months of monot-onous ‘interplanetary cruise’ to get back home. Except this time,the astronauts won’t be able to look forward to a trip to Mars.

To watch a video of the crew’s first Mars-walk, see:www.esa.int/SPECIALS/Mars500/SEMRCFOT1KG_0.html

For more information on the Mars500 project, including a down-loadable information kit, text and video diaries by the crew, andmuch more, see: www.esa.int/SPECIALS/Mars500

The crew will even answer your personal questions by email ([email protected]). Keep them short and think carefully – only the best questions will be relayed to them through ‘mission control’.

To find out how scientists envisage that Mars could be made habitable for humans, see:Marinova M (2008) Life on Mars: terraforming the Red Planet.Science in School 8: 21-24.www.scienceinschool.org/2008/issue8/terraforming

To learn more about the European Space Agency, see: www.esa.intFor a list of all ESA-related articles published in Science in School,

see: www.scienceinschool.org/esa

Diego Urbina andAlexandr Smoleevskiy ontheir simulated Marswalk

Science in School Issue 18 : Spring 2011

Image courtesyof ESA

/IPM

B

ESO: first super-Earth atmosphere analysed

Using the Very Large Telescope of theEuropean Southern Observatory (ESO), theatmosphere around a super-Earth exoplanethas been analysed for the first time. The plan-et, which is known as GJ 1214b and has 6.5times the mass of Earth, was studied as itpassed in front of its parent star and some of

the starlight passed through the planet’s atmosphere. We nowknow that the atmosphere is either mostly water in the form ofsteam or dominated by thick clouds or hazes.

GJ 1214b lies about 40 light-years from Earth in the constella-tion of Ophiuchus (the Serpent Bearer), and its planetary naturewas confirmed in 2009, also using ESO telescopes. Initial find-ings suggested that it had an atmosphere, which has now beenconfirmed and studied in detail by an international team ofastronomers, led by Jacob Bean (Harvard–Smithsonian Center forAstrophysics). “This is the first super-Earth to have its atmosphereanalysed. We’ve reached a real milestone on the road towardcharacterising these worlds,” says Bean.

To learn more, see the press release (www.eso.org/public/news/eso1047/) and the research paper:Bean JL (2010) A ground-based transmission spectrum of thesuper-Earth exoplanet GJ 1214b. Nature 468: 669–672. doi:10.1038/nature09596Download the article free of charge on the Science in Schoolwebsite (www.scienceinschool.org/2011/issue18/ eiroforum#resources), or subscribe to Nature today:www.nature.com/subscribe.

To find out more about the search for Earth-like exoplanets, see:Jørgensen UG (2006) Are there Earth-like planets around otherstars? Science in School 2: 11-16.www.scienceinschool.org/2006/issue2/exoplanet

Fridlund M (2009) The CoRoT satellite: the search for Earth-likeplanets. Science in School 13: 15-18.www.scienceinschool.org/2009/issue13/corot

and ESO exoplanet press kit:www.eso.org/public/products/presskits/exoplanets

For more information about ESO, see: www.eso.orgFor a list of ESO-related articles in Science in School, see:

www.scienceinschool.org/eso

Image

courtesyofESO

/LCalçada

An artist’s impression of the super-Earth exoplanet orbitingthe star GJ 1214. The planet appears as a large crescent inthe foreground with its red host star behind

4


www.scienceinschool.org 5

In November2010, the seven original members ofEIROforum were joined by a new, eighthmember: the European X-ray Free-Electron

Laser Facility (European XFEL), based in Hamburg, Germany.Like the other members of EIROforum, European XFEL is aEuropean inter-governmental research organisation (EIRO), fund-ed by member states.

The facility will produce ultra-short X-ray flashes which willenable scientists to map the atomic details of viruses, decipherthe molecular composition of cells, take three-dimensionalimages of the nano-world, film chemical reactions and studyprocesses such as those occurring deep inside planets. TheEuropean XFEL is currently under construction, and the first X-ray beams will be produced in 2014.

As a member of EIROforum, European XFEL will contributenot only to the funding, but also to the organisation and con-tents of Science in School. The editorial team are looking for-ward to welcoming a new member to the editorial board and toarticles about the work of European XFEL.

To learn more about European XFEL, see: www.xfel.eu

ESRF: shining light onto snake evolution

If you ask someone to describe whatcharacterises a snake, one of the answers islikely to be ‘no legs’. We know that thiswasn’t always the case – the ancestors ofsnakes probably looked similar to modernlizards, but over time, they lost their legs.How did that happen?

Scientists at the European Synchrotron Radiation Facility(ESRF) are helping to solve this puzzle using novel X-ray imag-ing technology to investigate a fossilised snake, Eupodophisdescouensi, which lived 95 million years ago in Lebanon, andhas two small limbs at its pelvis. The detailed 3D imagesrevealed that the internal architecture of these fossilised bonesstrongly resembles that of modern terrestrial lizard legs.Moreover, the results suggest that E. descouensi lost its legs notbecause they grew in a different pattern, but because they grewmore slowly, or for a shorter period of time, than those of theirlizard relatives.

To learn more, see the press release (www.esrf.eu/news/general/Snake-with-leg) and the (freely available) research paper:Houssaye A et al. (2011) Three-dimensional pelvis and limbanatomy of the Cenomanian hind-limbed snake Eupodophisdescouensi (Squamata, Ophidia) revealed by synchrotron-radia-tion computed laminography. Journal of Vertebrate Paleontology31(1): 2-7. doi: 10.1080/02724634.2011.539650

For a list of ESRF-related articles in Science in School, see:www.scienceinschool.org/esrf

To learn more about ESRF, see: www.esrf.eu

News from the EIROs

A detail of the Eupodophis descouensifossil, with a finger pointing to the leg

A montage of the mainEuropean XFEL buildingwith the undergroundexperiment hall


A silkworm: larva ofthe domesticatedsilkmoth

Image

courtesyof European

XFEL

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To learn how to usethis code, see page 1.

European XFEL:EIROforum’s new member

Image courtesy of arlindo71 / iStockphoto

ILL: a silken surprise

For about five thousand years, silk has been aprecious commodity, prized for its beauty, light-ness and strength. For three thousand years, theChinese managed to keep a monopoly on thelucrative silk trade by guarding the secret ofhow to produce it. Finally, however, the secret

got out: silk is produced by moth larvae, also known as silk-worms.

Even today, silk continues to fascinate us. For example, how isthe silk fibre assembled from the protein precursors inside thesilkworm? A recent study at the Institut Laue-Langevin used neu-tron beams to reveal some unexpected properties of silk pro-teins. Usually, proteins are stable at a concentration of approxi-mately 1 mg / ml, and only start to aggregate at a concentrationof about 5-10 mg / ml. The silk precursor proteins, however,behave very differently. The concentration inside the silkwormcan be up to 400 mg / ml and yet the proteins remain in solu-tion. When the concentration drops, however, the proteins beginto unfold and expand, eventually clumping together. Under labconditions, the effect is rather like a neat ball of string unravel-ling into a tangled mess, but inside the silkworm, order reigns:the insect controls the process, spinning the proteins into highlyordered silk filaments. These results are a big step towards under-standing the amazing properties of silks and how to synthesisethem and develop materials.

To learn more, see the press release on the ILL news website(www.ill.eu/nc/quick-links/news) or use the direct link:http://tinyurl.com/658slrp

See also the research paper:

Greving I et al. (2010) Small angle neutron scattering of nativeand reconstituted silk fibroin. Soft Matter 6: 4389-4395. doi:10.1039/C0SM00108B

To find out about previous ILL research into spider silk, see: Cicognani G, Capellas M (2007) Silken, stretchy and strongerthan steel! Science in School 4: 15-17.www.scienceinschool.org/2007/issue4/spidersilk

For a list of ILL-related articles in Science inSchool, see: www.scienceinschool.org/ill

To learn more about ILL, see: www.ill.eu


Science on Stage offers a plat-form for European scienceteachers to share their teaching

ideas, workshops and performances.Via national events, teachers competefor places at the Science on Stageinternational teaching festival, whichthis year will be held in Copenhagen,Denmark, on 16-19 Aprilw1. The 2011festival, with the motto of ‘Scienceteaching: winning hearts and minds’,will bring together 350 European sci-ence teachers.

France: Solar-powered curry andmusical sunshine

The French organisers of Science onStage, Science à l’Ecolew2, collaboratedwith a national science contest formiddle- and high-school studentscalled CGenial. On 15 May 2010, 81projects were presented in Nantes and12 teachers were selected to attend theinternational Science on Stage festivalthis year.

Guillaume Lebatard and AmandineSultana described how their students,aged 11-12, used little more than an

old satellite dish and some alumini-um foil to make a steaming hot gour-met meal. The foil was used to linethe surface of the dish, creating a par-abolic reflector capable of concentrat-ing the Sun’s energy. This solar cook-er proved sufficiently powerful to boilwater and even to make a deliciouschicken curry!

Mathematics teacher Francis Loretchallenged his 14-year-old students tobattle against him in the Internet’sbiggest virtual sailing race, theVendée Globew3. Students were givenexpert training in the basic principlesof sailing and in meteorology and theinterpretation of weather maps. Theyhad to grapple with the unfamiliarconcepts of spherical geometry, whichunderpin the calculations necessary tosail in the race. Of the 340 000 raceparticipants, Francis’s most accom-plished student sailor finished in animpressive 216th place.

Mozart, Bach, Beethoven,Rachmaninoff… and the Sun? Whowould have thought that in additionto sustaining all life on Earth, the Sun

also produces music? Jean-MichelLaclaverie and Elisabeth Martre’s stu-dents studied the frequency of vibra-tions emitted by the Sun and usedthem to show how this ‘music’ com-pares to that produced by more tradi-tional musical instruments.

Greece: Rainbows and MarsOn 15-16 October 2010, 3000 visitors

– including 2000 students – flocked tothe Hellenic Science on Stage eventw4

at the Laboratory Centre for PhysicalSciences of Aigaleo. There, teachersand students from across Greece pre-sented 110 high-school projects,including laboratory exhibits and twostudent performances.

Physics teacher Elias Kalogiroudescribed how his students designedexperiments to explain the wondersof the rainbow using their under-standing of optics; why is a rainbowcoloured, why is it bow-shaped andhow can we create one in the class-room? (Elias has also written an arti-cle on microscale chemistry for Sciencein School: see Kalogirou, 2010.)

www.scienceinschool.org6 Science in School Issue 18 : Spring 2011

Science on Stage brings together many ofEurope’s most innovative and inspiringscience teachers. Andrew Brown reviewssome of the recent national activities.

Science on Stage: countdown to the international festival


Using everyday materials, IoannisGatsios built 10 devices designed toteach his students about the behav-iour of gases. One consisted of aninflated balloon attached to a metalbottle. When the bottle was plungedinto liquid nitrogen at -190°C, the bal-loon deflated, illustrating that the vol-

ume of a gas is reduced by a decreasein temperature.

Theodoros Pierratos encouraged hisstudents to think like astronauts. Heasked them to consider everythingthat is required to plan a trip to Marsand live on its surface. Classroomexperiments helped answer questions

such as: how does the solar windaffect electronic equipment, and howcan we produce the energy requiredto maintain a manned base on Mars?(Theodoros’s work has also been fea-tured in Science in School. SeePatterson, 2009.)

Events


Image courtesy of G

uillaume Lebatard

Creating the parabolic reflector

Image courtesy of Guillaume Lebatard

Solar-powered cooking

Elias Kalogirou demonstrates why arainbow is bow-shaped

Image courtesy of Elias K

alogirou

Image courtesy of Elias K

alogirou


Image courtesy of Ioannis G

atsios

The balloon deflates whenthe metal bottle to which itis attached is immersed inliquid nitrogen


Web referencesw1 – To find out more about Science

on Stage Europe and to contactyour national organisers, see:www.science-on-stage.eu

w2 – To learn more about Science onStage France, see:www.sciencesalecole.org

w3 – Details of the Vendée Globe canbe found here:www.vendeeglobe.org/en

w4 – For more information aboutScience on Stage Greece, see:www.physics.ntua.gr/SOS-GREECE/contest.html

w5 – To learn more about the international festival and how toapply to take part, see: http://science-on-stage.eu/?p=3

ResourcesAfter each of the previous interna-

tional Science on Stage festivals (andthe Physics on Stage festivals that pre-ceded them), the Irish delegates pro-duced a book describing how to carryout their favourite experiments in the

festival. These books can be down-loaded free of charge from the Scienceon Stage Ireland website:www.scienceonstage.ie/resources.html

To view all other Science in School articles about Science on Stage, see:www.scienceinschool.org/sons

Andrew Brown recently graduatedfrom the University of Bath, UK, witha degree in molecular and cellularbiology. During his course, he took ayear out to work for the agrochemicalcompany Syngenta where he spe-cialised in light and electronmicroscopy. He now works as anintern for Science in School, based atthe European Molecular BiologyLaboratory in Heidelberg, Germany.

Image courtesy of Theodoros Pierratos

Investigating how solar windaffects electronic equipment

Image courtesy of Theodoros Pierratos

Attending the international festival

At each national Science on Stageevent, a fixed number of teacherswere selected to represent their coun-try at the international Science onStage festival in Copenhagen. Forthese teachers, participation will befree.

For other science teachers who wishto attend the international festival,there are a limited number of placesfor which a registration fee will becharged. See the Science on Stagewebsite w5 for details.

ReferencesKalogirou E (2010) Microscale chem-

istry: experiments for schools.Science in School 16: 27-32.www.scienceinschool.org/2010/issue16/microscale

Patterson L (2009) A classroom inspace. Science in School 12: 50-54.www.scienceinschool.org/2009/issue12/spaceclassroom


Dimistra Milioni, president of theeducation council of the municipalityof Aigaleo, learns about the ‘capaci-tor in action’ project at the Scienceon Stage Greece event. The munici-paty of Aigaleo is the main sponsor ofScience on Stage Greece


Kristina Aare, winner of the2009 EMBL prize at EUCYS

In September 2009, in the Palais dela découverte in Paris, France, 132young scientists aged 14 to 21

from Europe and beyond cametogether for the 21st European UnionContest for Young Scientists(EUCYS)w1 (see Rau, 2009). As part ofthe contest, participants presentedoriginal projects from all corners ofscience and competed for prizes whilesampling some of Paris’s world-famous culture and getting to knoweach other. In addition to the main

prizes from the European Union, anumber of special prizes are awardedeach year, including one-week visitsto the EIROforumw2 institutes – agroup of seven (now eight) researchorganisations around Europe, incor-porating some of the world’s mostexciting science. One of the luckywinners in 2009, I will share with youmy experiences and those of fourother winners of the EIROforumprizes that year.

Kristina Aare – studying bacteriain polluted water

“My interest in science started insecondary school, with a focus onbiology and chemistry, which led tomy successful participation in a num-ber of national competitions in myhome country of Estonia. My mainpassion is biochemistry, so I decidedto work on the project which was towin the European Molecular BiologyLaboratory [EMBL]w3 prize atEUCYS.”


Young scientists at thecutting edge: EIROforumprize winners

Courtney Williams, winner of the CERN prize at the EuropeanUnion Contest for Young Scientists 2009, reports on her experiences and those of the other EIROforum prize winners.

Jake Martin with hiswinner’s certificate

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Damian Steiger in frontof ESRF

Courtney Williams pays avisit to the CERN library

Kristina’s research was dedicated tothe problem of environmental pollu-tion with oil. She studied the soil bac-terium Pseudomonas putida, which hasan extremely high tolerance of phe-nol, toluene and other toxic organicsolvents found in oil. She is reallylooking forward to her visit to EMBLin Heidelberg, Germany, and theinsights this will provide her with.

Jake Martin – developing a newway of creating fuel

Jake travelled halfway around theworld to compete in EUCYS – fromAuckland, New Zealand – and thenagain when he visited Culham, UK,for his visit to the European FusionDevelopment Agreement - JointEuropean Torus (EFDA-JET)w4.

Jake, now 19, has been competing inscience fairs since he was 14. HisEUCYS project consisted of a gasifierhe built, which turns wood into a fuelgas that can run a normal petrolengine. Another output of his gasifieris biochar, a type of charcoal you getfrom pyrolising biomass. The primaryuse of biochar is not as a fuel, howev-er, but to take carbon dioxide out ofthe atmosphere. For his prize Jake vis-ited the EFDA-JET facility, whichitself is looking at alternative methods

of generating energy: it is the onlyoperational fusion experiment capableof actually producing fusion energy.He received advice and informationfrom scientists working there, andlearned more about how internationalco-operation plays a part in Europeanscience – a lot more so than in NewZealand.

Damian Steiger – building aminiature particle accelerator

“My project was to design andbuild a small cyclotron, small enoughto fit on a desk. Therefore, I tried toapply as many new technologies aspossible to the design of the firstcyclotron, built in the 1930s. With myproject I showed a way of buildingsmall cyclotrons with state-of-the-arttechnology and at low cost. In futuresome of the knowledge might be usedto build small and compact cyclotronsfor medical applications or materialsresearch.”

For his prize, Damian went to theEuropean Synchrotron RadiationFacility (ESRF)w5 and the Institut LaueLangevin (ILL)w6 at their joint campusin Grenoble, France, where he visitedall the different laboratories and con-trol rooms. “I enjoyed the visit to thereactor at ILL most,” he says. “The

blue glow of the reactor due to thecharacteristic Cherenkov radiationwas especially impressive. At themoment I am studying physics atETH Zürich, Switzerland, and thanksto my visit to ESRF and ILL, I have abetter idea of which field I want towork in afterwards.”

Julian Petrasch – tracking asteroids from the computer

In his winning project, ‘SkyAlignment Simulator (SAMS) –improved determination of minorplanet positions’, Julian Petrasch fromGermany developed software tomeasure the positions of asteroidsmore precisely. The 17-year-old usedthe new software to pinpoint the posi-tions of about 20 asteroids and twospace probes. He reports that somepublications on this topic from theBerlin Observatory have already useddata processed with this new method.

As the winner of the ESO prize,Julian enjoyed the trip of a lifetime totwo of ESO’sw8 observatories in Chilefrom 7 to 13 February 2010. “It wasamazing to walk between these gianttelescopes and see how such largemachines can be controlled andmoved so precisely just by one per-son,” he said after his visit to Paranal

Events


Julian Petrasch visiting theParanal Observatory in Chile

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Observatory. Julian, who became anamateur astronomer when he wasonly six years old, also feels deeplyimpressed by Chile, its nature, itsenormous distances and the astonish-ing silence of the desert.

Courtney Williams – investigatingunderwater neutrino detection

Unlike for many other contestants,EUCYS was my first international sci-ence fair. My project, ‘Listening forghost particles: the acoustic cosmicray neutrino experiment’, had twoaspects: analysing background noisefrom an underwater neutrino detec-tor, and simulating the acoustic pulsesthat high-energy neutrinos shouldmake when they enter water.

EUCYS was a great experience andone of the best weeks I’ve ever had –quite apart from winning a prize. Asit happens, I was lucky enough to beawarded the CERNw7 prize: when Ivisited the institute this summer, Ienjoyed learning about how all thedifferent detectors work, as well astalking to people from differentdepartments, including the pressoffice, the director general and theengineers. My trip has intensified mydesire to work in neutrino astro-physics and I’m really eager to goback to CERN!

Further EIROforum winnersThe other EIROforum winner at

EUCYS 2009 was Ana Shvetsova fromRussia. Ana, who designed a vehicleto move on Venus, was awarded theEuropean Space Agencyw9 prize. Sheexplained her project in an onlinevideow10.

With the 22nd EUCYS event, whichtook place in 2010 Lisbon, Portugal(see Rau, 2011), the number of youngscientists visiting the EIROforumorganisations continues to grow.

ReferencesRau M (2009) Discoveries in Paris: the

European Union Contest for YoungScientists. Science in School 13: 6-9.www.scienceinschool.org/2009/issue13/eucys09

Rau M (2011) Young minds in science:the European Union Contest forYoung Scientists 2010. Science inSchool 18: 13-16.www.scienceinschool.org/2011/issue18/eucys2010

Web referencesw1 – Find out more about the

European Union Contest for YoungScientists on their website:http://ec.europa.eu/research/youngscientists

For a preview of the 2011 contest tobe held in Helsinki, Finland, see:http://eucys2011.tek.fi

w2 – To learn more about EIROforumand its research organisations, see:www.eiroforum.org

w3 – The EMBL website can be foundhere: www.embl.org

w4 – To find out more about EFDA-JET, see: www.jet.efda.org

w5 – Visit the website of ESRF formore information: www.esrf.eu

w6 – To learn more about ILL, see:www.ill.eu

w7 – For more information aboutCERN, see: www.cern.ch

w8 – Learn more about ESO online:www.eso.org

w9 – Find more information on ESAon their website: www.esa.int

w10 – To watch Ana Shvetsovaexplain her project (in English withFrench subtitles) see thewww.universcience.tv website oruse the direct link:http://tinyurl.com/5vy9yub

ResourcesTo read Courtney’s full report on her

stay at CERN and her experience asa EUCYS participant, see her blog:www.butrousfoundation.com/ysjournal/?q=blog/70

To learn more about the individualEIROforum institutes, see:

EIROforum (2010) EIROforum:introducing the publisher of Sciencein School. Science in School 15: 8-17.www.scienceinschool.org/2010/issue15/eiroforum

Courtney describes how she came tobe interested in physics in an articlein Symmetry:www.symmetrymagazine.org/cms/?pid=1000859

If you enjoyed reading this article,browse our collection of eventreports online:www.scienceinschool.org/events

Courtney Williams is studying theoretical physics at Imperial CollegeLondon, UK. Her main interests lie inneutrino physics and science commu-nication. She has worked at theUniversity of Sheffield andRutherford Appleton Laboratory, andwritten articles for publicationsincluding IoP Interactions, E&TEducation and Symmetry. She isinvolved in promoting physics toyoung people as a British ScienceAssociation CREST Alumnus,Ignition Creative Spark and STEMambassador. Her personal website canbe found at courtneywilliams.co.uk.


Image courtesy of techengine / iStockphoto



Events


Asunny afternoon in Lisbon –boatmen set sail from theshores of the River Tejo,

evoking thoughts of the many greatexplorers that have ventured forthfrom here to discover uncharted terri-tories. It is a late September day in2010, and in the nearby ElectricityMuseum, 124 vibrant minds from 37countries are presenting their ownventures into science.

The hall is abuzz with young con-testants (aged 14-21) who have trav-elled from across Europe and beyond.We, the 18 members of the interna-tional jury, have a tough time choos-ing among these excellent projects:how can you compare the design of aflat-packed Christmas tree withbehavioural studies of birds; a collec-tion of Moroccan folk tales with a digfor dinosaur bones; face-recognition

Young minds in science: theEuropean Union Contest forYoung Scientists 2010Marlene Rau reports on the 22nd European UnionContest for Young Scientists (EUCYS).

Lisbon’s ElectricityMuseum, host tothe 2010 contest

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algorithms with improved methodsfor wastewater treatment; a gadgetfor identifying fraudulent drycleanerswith a study on whether Internetaddiction causes brain lesions?

The European Union suggests agood recipe for creating a winningproject: “Choose a subject that inter-ests and inspires you (the idea mustof course be an original one). Add alittle curiosity and know-how, a touchof perseverance and obstinacy, someadvice from specialists, a good pinchof ingenuity, a large measure of a crit-ical mind, enthusiasm and an enter-prising spirit and, above all, the bestpart of your imagination.”

While the jury is locked in fiercediscussions behind closed doors, thecontestants explore Lisbon and itssurroundings: they dance the


quadrille with costumed guides in thebaroque palace in Mafra; dine in theadjoining monastery, served by sol-diers training for conflict zones; listento talks on biodiversity and patenting;and satisfy their curiosity in the‘Explore’ room at the Park of NationsKnowledge Pavilion: can you touch atornado? Are all shadows just blackand white?

And of course, there is much toexplore inside the ElectricityMuseum, too: during the breaks, stu-dents peruse the museum’s marvel-lous interactive exhibition.

Finally, the 26 prizes are allocated.First-prize winners are MiroslavRapcak and David Pegrimek from theCzech Republic, who computer-pre-dicted a complete phase diagram ofCO2 nanoclusters; Márton Balassi andDávid Horváth from Hungary, whodeveloped a computer simulation ofecosystems for the classroom, whichcan also be used for risk assessment;and Lukasz Sokolowski from Poland,who studied the foraging strategy ofthe ant Formica cinerea.

The ten main prizes sponsored bythe European Union are complement-ed by a range of prestigious specialprizes, including those offered byEIROforumw1: seven one-week stays atone of its member organisations, eachof which is awarded to a worthy par-ticipant who would profit from a visitto that institute.

Volha Shumskaya (aged 17) fromBelarus will travel to CERNw2, theEuropean Organization for NuclearResearch in Geneva, Switzerland,where enormous amounts of data aregenerated and processed every day.This enthusiastic mathematician hasstudied the extrema of least commonmultiples and greatest common divi-sors for sequences of numbers. JanisSmits (aged 18) from Latvia is theproud winner of a visit to the fusionreactor at EFDA-JETw3 in Culham, UK.Like his host organisation, Janis isconcerned with improving energygeneration, and has developed a lightthin-layer lithium iron phosphate bat-tery to propel his bicycle.

Vladimíra Bejdová (aged 19) fromthe Slovak Republic will visit theEuropean Space Agencyw4. The spaceenthusiast has discovered andanalysed a new binary star in theAndromeda constellation using asmall telescope.

The biologist among theEIROforum prize winners is RaghdRostom (aged 19) from the UK. Heruse of cells from embryonic chickbones as a model for osteogenic ver-sus chondrogenic differentiation instem cells won her a visit to theEuropean Molecular BiologyLaboratoryw5 in Heidelberg, Germany.Young astronomer Pavel Fadeev(aged 19) from Israel will travel to theEuropean Southern Observatory’sw6

telescopes in Chile, where he can dis-cuss his unique catalogue of 270extragalactic star-forming regionswith professional colleagues.

Maths enthusiast Radko Kotev(aged 18) from Bulgaria was awardeda trip to the Institut Laue-Langevin(ILL)w7 for finding a new solution tothe geometrical Apollonius problem –

The winners of theEuropean Union prizes atEUCYS 2010

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Francesco Romanelli, director general ofEFDA-JET and chairman of EIROforum,presents the ILL prize to Radko Kotev. Inthe background, CERN prize winnerVolha Shumskaya (left) and ESA prizewinner Vladimíra Bejdová (right)


constructing a circle that is tangentialto three given circles. He will bejoined at the campus of ILL and theEuropean Synchroton RadiationFacility (ESRF)w8 in Grenoble, France,by ESRF prize winner SebastianCincelli (aged 19) from Italy, a youngengineer who designed ‘social’ robotson wheels for exploring unchartedareas.

Read about these and all otheraward winners and their projects onthe EUCYS 2010 websitew9.

Apart from explaining their projectsto the jury, the contestants also havethe chance to present their work to thegeneral public. Over 3000 studentsfrom schools across Portugal visit theEUCYS stands and marvel at theirpeers’ ingenuous ideas. This may laythe foundation for the next generationof EUCYS contestants. The event doeshave an impact, as João Amaral (aged21) is well aware – one of the manyPortuguese student helpers, he washimself a contestant in EUCYS 2007.These helpers not only solve anyminor or major problems the contest-ants have, and guide them throughtheir social programme, but this yearalso give their own set of awards at

Events


Contestantsexchangingideas

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the final ceremony, in 14 categoriessuch as ‘the funniest’, ‘the mostenthusiastic’ or ‘the most Portuguese’project (which goes to the Braziliancontestant).

The impact of EUCYS is somethingMaximos Tsalas from EFDA-JET canvouch for, too – together with ClausHabfast from ESRF, he offered anenjoyable evening of lectures on ener-gy to the students, demystifying theconcept of fusion energy, to coincidewith the theme of the ElectricityMuseumw10. “EIROforum has been apart of this contest for many years,and last year’s winner is currentlyvisiting EFDA-JET, working with us,”says Maximos. “We are always look-ing for bright minds, so we offerselected participants the opportunityto visit EIROforum organisations.”

And what is the contestants’ ver-dict? “I’m certain we will carry thesememories with us for the rest of ourlives: to meet other young scientists,to understand their projects and toshare some ideas are our main goalsduring these days,” explains GuodaRadaviciute from Lithuania.

EUCYS is a great experience foreveryone involved – and we arealready looking forward to EUCYS2011 in Helsinki, Finlandw11.

Web referencesw1 – For more information about

EIROforum, see:www.eiroforum.org

w2 – To learn more about CERN, see:www.cern.ch

w3 – More information about EFDA-JET is available here:www.jet.efda.org

w4 – To learn more about theEuropean Space Agency, visit:www.esa.int

w5 – For more details about theEuropean Molecular BiologyLaboratory, see: www.embl.org

w6 – More information about theEuropean Southern Observatory isavailable here: www.eso.org

Sandro Young from Canada demonstrates his 3D user interface

Image courtesy of the Portuguese Youth Foundation, Host Organiser of EUCYS 2010


Dinner in the refectory of the Mafra monastery

w7 – For more information about theInstitut Laue-Langevin, see:www.ill.eu

w8 – To learn more about theEuropean Synchroton RadiationFacility, visit: www.esrf.eu

w9 – The EUCYS 2010 websiteincludes information about all par-ticipants, their projects and the con-test, along with many pictures andvideos: www.lisboa.eucys2010.eu

Further movies are available on theEUCYS YouTube channel. See:www.youtube.com/user/EUCYS2010

w10 – The slides of Claus Habfast’sand Maximos Tsalas’s lectures canbe downloaded from the Science inSchool website:www.scienceinschool.org/2011/issue18/eucys2010#resources

w11 – Learn more about the 2011 edi-tion of EUCYS in Helsinki and entertheir slogan competition. See:http://eucys2011.tek.fi


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ResourcesFor more information on EUCYS, see

the European Commission website:http://ec.europa.eu/research/youngscientists

To find out more about the nationalcompetitions and to contact yournational organiser, see:http://ec.europa.eu/research/youngscientists (under ‘who isinvolved?’)

Read about how last year’s winnersenjoyed their EIROforum visits:

Williams C (2011) Young scientistsat the cutting edge. Science in School18: 10-12.www.scienceinschool.org/2011/issue18/eucys2009

To learn more about energy, the topicof the EIROforum lectures atEUCYS, see the Science in Schoolseries of energy articles:www.scienceinschool.org/energy

Learn more about EIROforum and theresearch performed at its organisa-tions here:

EIROforum (2010) EIROforum:introducing the publisher of Sciencein School. Science in School 15: 8-17.www.scienceinschool.org/2010/issue15/eiroforum

If you enjoyed reading this article,take a look at the full collection ofevent reports published in Science inSchool. See:www.scienceinschool.org/eventreports

Dr Marlene Rau was born inGermany and grew up in Spain. Afterobtaining a PhD in developmentalbiology at the European MolecularBiology Laboratory in Heidelberg,Germany, she studied journalism andwent into science communication.Since 2008, she has been one of theeditors of Science in School.

Image courtesy of the Portuguese Youth Foundation, H

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Contestants from the CzechRepublic analysed the habitatpreferences of black (right) andcommon (left) redstarts. Unlikethe males, females (middle) arevery similar in both species

Dancing the quadrille


Feature article

www.scienceinschool.org Science in School Issue 18 : Spring 2011

Be thou like the dunnock – themale and female impeccablyfaithful to each other,” said

Reverend Frederick Morris in 1853. Inan attempt to preach fidelity, heencouraged his parishioners tobehave like dunnocks (Prunella modu-laris) – small, brown, rather plain-looking birds. Far from being monog-

amous, however, the dunnocks – froma Victorian point of view – haveshockingly lax morals, with thefemale often mating with severalmales. What would Reverend Morrishave made of the scandalous truth?

Tim Birkhead, professor of behav-ioural ecology and the history of sci-ence at Sheffield University, UK, has

“

BiologyEvolutionAnimal BehaviourAges 16+

If “nothing in biologymakes sense except in thelight of evolution”(Theodosius Dobzhanky,1900-1975) this articlewill be appealing andenjoyable for all biologyteachers. It focuses onProfessor Tim Birkhead,his life and his research,but also introduces anoth-er interesting topic – ani-mal promiscuity and sex-ual selection – which isprobably new for manyreaders and uncommonin teaching evolution atschool.

The article is based on aninterview, so the style ispleasant and witty; more-over some difficult points(sperm competition andsperm choice) areexplained in a clear andvivid way (for instance, inthe synthesis of the battleof sexes, as “maximumfertilisation versus bestfertilisation”).

The story of Birkhead’s lifeand career is interestingand inspiring for youngstudents attracted by thestudy of animal behaviourand evolution; his person-al methodology in teach-ing the history of sciencewill also provide scienceteachers with new andstimulating ideas.

Finally, this article showsthat the study of evolutionis an ever charming andsurprising adventure.

Giulia Realdon, Italy

Battle of the birds:interview with TimBirkheadTim Birkhead tells Karin Ranero Celius about promiscuous birds and teaching science students.

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devotednearly 40 years to the

study of promiscuity in birds. FromDarwin’s time up to the late 1960s itwas thought that male animals com-peted for female partners, with thestrongest and most attractive malesimpregnating the most females, andthat females sought only the securityof monogamy, copulating with multi-ple partners only when forced. Theunladylike truth that graduallyemerged, however, is that females of

most species activelyseek multiple partners

to mate with, an evolu-tionary strategy to get the

very best sperm to fertilisetheir eggs.Indeed, rivalry between

males and discrimination byfemales extends beyond the sexu-

al act itself. Inside the female, thesperm of different males fight forsupremacy – this is sperm competi-tion. At the same time, the femalemay be able to select the sperm thatare best for her – this is sperm choice.This is the true battle of the sexes. Themales and females of each species arepermanently locked in a struggle toout-evolve each other, as their repro-ductive anatomy and behaviourchange to achieve their conflictingaims: maximum fertilisation versusbest fertilisation.

These radical ideas were just begin-ning to emerge when Tim Birkhead

graduated from university in 1972. “Ijust feel incredibly fortunate to havebeen the right age, at the right placeand the right time,” he says.

Tim’s initial interest was in seabirds. In 1972, he started a project tomonitor guillemots on Skomer Island,a nature reserve in Wales: he lookedat the adult and immature survivalrates and the age of the first breedingand reproductive success, as well asassessing the effects of oil pollutionand climate change on the popula-tion. Although the project continuesand he returns to Skomer Island regu-larly, the focus of his research gradu-ally moved towards sex. In particular,post-copulatory sexual selection.

Tim Birkhead’s research has helpedto re-shape our understanding of birdmating systems. Why should a bird oran individual copulate with morethan one partner? What determineswhich male fertilises the female’s eggswhen she has mated with several

Image courtesy of Francesca Birkhead

The ever-faithful

dunnock

Tim Birkhead with a zebra finch,Taeniopygia

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lots of wonderful birds. As we walkedback at the end of the day, a youngman sat looking through a telescopewith a notebook and my dad justlooked at me and said: ‘You could dosomething like that when you get old-er’.” And he did.

But Tim is not always the observer;often, he is the one in the spotlight. Agood scientist must be able to com-municate his research and engageaudiences by making it relevantand Tim does just that: he illus-trates science with many sto-ries, and he’s clever, funny, per-suasive and very clear. In fact,he is one of those teacherswhose lectures should be sched-uled early in the morning tomake it worth the students’ whileto get out of bed. What makes hislessons so special? His enthusiasm issurely part of the answer.

partners? And how are sexual con-flicts resolved? His research involvesfinding out what happens to thesperm of the male inside the female’sreproductive tract and investigatingthe importance of sperm competitionand sperm choice in determiningwhich male fertilises the eggs.

In his ongoing quest to explore thenature of sexuality, Tim Birkheadcould be considered a paparazzo ofnature – travelling to remote islandsand bearing extreme discomfort in thehope of catching birds mating, andwhen they do, splashing their mostintimate details and pictures over thepages of science journals.

Tim’s passion for birds goes wayback – to when he was 11. “On onememorable holiday in Wales, myfather took me to a little island calledBardsey Island – one of the mostbeautiful places in the world, with

Field courses and tutorials are Tim’spreferred teaching methods. “I thinkintellectual development hinges verystrongly on personal exchange.Tutorials are important for students tohear us talking to them, and for themto answer so that we can help shapetheir arguments. In field courses, sim-ilarly. I love teaching field coursesbecause you can see the kids grow inthat week. I teach a field course thattakes place in June. The first day isappalling, but by the end of the weekthey are fantastic. However, they havetrouble retaining that knowledge andenthusiasm, so when they come backin September it’s as if nothing hashappened. I feel we ought to be doingfour or five field courses, and by theend of that time a lot of the informa-tion and enthusiasm and way ofdoing science would have stuck.”

Doing science is important, but so isunderstanding science itself. “The his-tory of science course that I teach isabout doing science and what itmeans to be a scientist. I try to teach itin an unconventional way: I don’t letmy students take notes because Iwant them to listen, to be inspired bywhat I tell them and then go off anddo the necessary reading. For one ofthe major assessments, I take them toa place where, based on their readingand a quote I give them, they have toorganise a conference for the day. It’s


The guillemot

Artist’s impression of the

moment of fertilisa-tion: a sperm gains

entry to an ovum

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ResourcesTo learn more about Tim Birkhead,

see:www.sheffield.ac.uk/aps/staff/acadstaff/birkhead.html

To see one of Tim Birkhead’s talks,see:www.thedolectures.co.uk/speakers/speakers-2009/tim-birkhead

Another talk by Tim Birkhead (‘Theearly birdwatchers’) can be watchedon TED, an online collection of lectures:www.ted.com/talks/tim_birkhead_the_wisdom_of_birds.html

To learn more about research intodunnock promiscuity, see:

Davies, NB (1983) Polyandry, cloaca-pecking and sperm competi-tion in dunnocks. Nature 302: 334-336. doi: 10.1038/302334a0

Download the article free of chargefrom the Science in School website(www.scienceinschool.org/2011/ issue18/birkhead#resources), orsubscribe to Nature today:www.nature.com/subscribe

Haubold B (2007) Review of TheSelfish Gene and Richard Dawkins:How a Scientist Changed the Way WeThink. Science in School 5: 84-85.www.scienceinschool.org/2007/ issue5/selfish

up to them entirely how they inter-pret it, and how they give the presen-tation, and everybody does it verydifferently. They learn about the histo-ry of science by listening to theirpeers.”

Tim also enjoys sharing his enthusi-asm for science with school students.“Two or three weeks ago I gave a talkat a school where the students wereincredibly mature. As I said, most ofmy research is on sexual selection andreproduction, and I was a bit appre-hensive about telling 16- and 17-year-olds about reproduction, but theywere fantastic. They asked reallyinnovative questions, and there wasn’tany silly giggling. I think with agroup like that, you could really getacross what science is, although withother types of kids it might be a bitdifficult.”

What would Reverend Morris havemade of that talk, I wonder? Perhapshe too would have concluded that hewould have been better preaching tothe dunnock about the virtuous waysof the human.

This article is based on an interviewwith Tim Birkhead, as well as his lecture‘Darwin and post-copulatory sexualselection’ at the 11th EMBL / EMBOScience and Society Conference: TheDifference between the Sexes – FromBiology to Behaviour, on 5-6 November2010.

Dawkins R (2006) The Selfish Gene, 3rd

edition. Oxford, UK: OxfordUniversity Press. ISBN:9780199291151

To see all previously published fea-ture articles in Science in School, see:www.scienceinschool.org/features

Karin Ranero Celius obtained abachelor’s degree in physics and psy-chology, and then an MSc in museumstudies. Her passion for educatingothers about the wonders of scienceled her to become a science communi-cator, concentrating mainly on out-reach and education, first at the IAC(Instituto de Astrofisica de Canarias) inthe Canary Islands, Spain, and then atthe European Southern Observatoryin Munich, Germany. While writingthis article, she was based at theEuropean Molecular BiologyLaboratory in Heidelberg, Germany,and she now works for EJR-Quartz inLeiden, the Netherlands.

Image courtesy of A

lasdairJames / iStockphoto

Bardsey Island, North

Wales



Cutting-edge-science


In the foothills of the Himalayasgrow trees, five to ten metres tall,with clusters of small oval leaves

and delicately perfumed cream-coloured flowers. These are Moringaoleifera – the most widely cultivated ofthe 14 species of the genus Moringa,known as ‘miracle trees’.

“It is called a miracle tree becauseevery part of the tree has benefits,”says Balbir Mathur, president of Treesfor Life Internationalw1, a US-basednon-profit organisation that providesdevelopmental aid through plantingfruit trees, moringas among them.“The roots, leaves, bark, parts of thefruits and seeds – everything. The listis endless.”

Reports in the press about themiraculous nature of the tree may beexaggerated, but it does have sometruly impressive properties. Native tonorthern India but now found widelyin Asia, Africa and Latin America,moringas have been used in villagesin developing countries for hundredsof years, their uses ranging from tra-ditional medicine, food and cookingoil, to natural pesticide, domesticcleaning agent, and – the latest addi-tion – biofuel.

Moringas are extremely hardy,known in parts of Africa as nebedies,meaning ‘never-die trees’, becausethey grow on marginal soils, regrowafter being chopped down, and are

one of the few trees that produce fruitduring a drought.

It is yet another useful property ofMoringa oleifera, though, that is excit-ing scientists: when crushed, moringaseeds can help purify dirty water.This could save lives: the WorldHealth Organization estimates thatunsafe water, poor sanitation andinadequate hygiene cause about 1.6million deaths a year globally.

Water purification is mainly a two-step process: initially, water is clari-fied, removing particles such as min-erals, plant residues and bacteria.However, since not all particles readi-ly sink to the bottom, coagulatingagents are added to help clump theparticles together; these clumps canthen be removed by filters or sedi-mentation. The second step is disin-

fection, to kill those pathogens thatstill remain, using chlorine com-pounds, ozone, hydrogen or ultravio-let light.

Moringa oleifera can help with thefirst purification step – not only in thedeveloping world but also in thedeveloped world. In industrial watertreatment plants, the most prevalentcoagulating agents used today arealuminium salts. Most particles thatneed to be removed from water arecharged, so coagulating agents areusually ions; because the coagulatingefficiency increases with the square ofthe coagulating agent’s ionic charge,polyvalent ions such as aluminiumare very efficient. However, there isconcern – albeit controversial – thatlong-term exposure to aluminiummay be associated with the develop-

Moringa: the science behind the miracle treeMoringas have long been known as miracletrees. Now scientists are investigating theirproperties in depth, as Sue Nelson andMarlene Rau report.

Moringa leavesA flower from a

moringa tree

A moringa pod

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, Loughborough University



This is a thought-provoking article that uses theoreti-cal science (binding abilities of ions, neutron reflec-tion techniques) to explain a real-life situation (usingseeds to purify water).

Ideas from this article could be used with students ofall ages to carry out some innovative practical work,with appropriate risk assessments. M. oleifera seedscan be bought via the Internet, if you are not luckyenough to have them grow locally, and their effectson clarifying water can be compared to those of otherseeds. Are M. oleifera seeds really much better?Younger students could have a lot of fun grinding updifferent seeds and coming up with different ways ofmeasuring how clear their dirty water becomes.

Older students could take this further and carry outinvestigations linked to using different parts of theseeds and relating this to seed biochemistry, or com-pare seeds treated in different ways, e.g. dried versusfresh. Researching the scientific basis of the seed-driven clarification process would certainly be chal-lenging for the most able students.

The article fits well into a number of curricular top-ics: biology of seeds / biochemistry of extracts; chem-istry of water purification / physical behaviour of thesalts; physics – perhaps something to do with investi-gating density of layers – and looking at alternativemethods. The idea could form the basis of a cross-curricular project with social science lessons,because of the good links with sustainability andrenewable resources.

The article is suitable as a comprehension exercisefor students aged 16 and older. Possible questions toask in a biology lesson include:

· Moringa oleifera is just one of 14 species of the‘miracle tree’. Which part of the scientific namegives the genus, and which the species?(Answer: genus: Moringa; species: Moringa oleifera)

· In this article, a variety of uses are given for themoringa, including medicine, food, and cookingoil. Suggest which parts of the tree might be usedfor which of the given uses in the article.(Answers need not be correct, as students are notexpected to know, but they should be reasonablesuggestions, e.g. oil from seeds; medicine fromany part; food from fruit; pesticide from leaves;cleaning agent from roots.)

· Moringas ‘regrow after being chopped down’ andare also described as being ‘one of the few treesthat will produce fruit during a drought.’ Suggestwhat adaptations these trees might possess inorder to do this.(Answer: again, students would not be expectedto know the answer, but could come up with pos-sible ideas such as new trees growing from seedsthat were dispersed before the tree was cut down,or the chopping down acting as a kind of coppic-ing, causing more branches to grow. Being able toproduce fruit during a drought could be due to anextensive root system (deep and / or wide, likethose of cacti), to leaves that reduce the transpira-tion rate, or to mechanisms for absorbing dew,such as shallow roots.)

The article can also form the basis of discussion.Possible topics include:

· The evidence for / against aluminium being impli-cated in neurodegenerative diseases

· The more unusual uses of plants

· The role of the media in scaremongering the pub-lic on flimsy scientific basis (such as the drop insales of aluminium saucepans, after it was pro-posed that they may be harmful)

· Citizenship topics and / or theme days based onwater availability around the world.

Sue Howarth, UKRE

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BiologyChemistryBiochemistryPhysicsPersonal, social and health educationAges 7-18

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The M. oleifera tree




ment of neurodegenerative diseases.Iron salts are an alternative, but theyare more difficult to use, as their solu-bility changes with pH.

Further kinds of coagulating agentsinclude synthetic polymers, but, aswith the other coagulants, the sludgeformed in the clarification processneeds to be disposed of: so eventhough synthetic polymers solve theproblem of the putative link to neu-rodegenerative diseases, their lack ofbiodegradability is an issue.

Since M. oleifera is both non-toxicand biodegradable, and reportedreductions in the cloudiness, clay andbacterial content of water after theapplication of M. oleifera seeds rivalthe efficiency of aluminium salts (seeGhebremichael et al., 2005), it seemsto be a viable alternative.

In certain rural areas of Sudan,women already use M. oleifera to puri-fy water: when collecting water fromthe River Nile, they place the pow-

dered seeds in a small cloth bag witha thread attached. This is then swirledaround in the bucket of turbid water,until the fine particles and bacteriaclump together with M. oleifera pow-der, sinking and settling to the bot-tom. For drinking water though, thewater needs to be purified further –by boiling, filtering through sand orplacing it in direct sunlight in a clearbottle for a couple of hours (solaris-ing; see Folkard et al., 1999). You cantry a similar technique yourself inclass (see box on page 24).

Although a successful pilot studywas performed at Thyolo water treat-ment works in Malawi in 1989-1994(see Folkard & Sutherland, 2002),developing future industrial treat-ment methods from M. oleifera relieson knowing exactly what processestake place during the purification.Researchers already know that theactive ingredient in the seeds is pro-tein, which accounts for 30-40% of theseeds’ weight. There are at least twoproteins that may be active: they arewater-soluble and quite small, about6-16 kDa, so they can readily diffuseout of the cloth bags. At higher con-centrations, they aggregate even insolution due to their substantialhydrophobic regions. The proteinadsorbs on to contaminant particles,which then clump together and canbe separated and extracted.

But how exactly does this clumpingwork? Scientists from the Universityof Uppsala, Sweden, and the

Image courtesy of Dr Majority Kwaambwa, University of Botswana

Moringa seeds: whole (left) andcut open (right)

© WEDC, Loughborough University

Moringa oleifera

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Seeds of the Moringa oleifera tree are cheaply availableonline, as the tree is grown for decorative purposes.

Water will require different amounts of M. oleifera pow-der to purify it, depending on the impurities present.Around 50-150 mg of ground seeds treat one litre ofwater: as a rule of thumb, powder from one seed will besufficient for one litre of very turbid or two litres ofslightly turbid water. Experimenting with small amountsof water in a jar will help you work out the correctamount of powder and the optimal stirring times.

You may want to compare the water quality achievedwith M. oleifera seeds to that achieved with othermethods (see Mitchell et al., 2008, for an example ofa different water purification method), and run a com-petition for the most efficient method of water purifi-cation.

1. Remove the seeds from the dried pods, if still pres-ent, and shell them, leaving a whitish kernel.Discard any kernels with dark spots or other signsof damage.

2. Crush the seed kernels to a fine powder and sievethem (0.8 mm mesh or similar).

3. Add the powder (approximately 2 g) to one cup ofclean water, pour into a bottle and shake for 5 min-utes.

4. Filter the mixture through a clean cloth into abucket of dirty water that is to be treated.

5. Stir the water quickly for 2 minutes and slowly for10-15 minutes (do not use metal implements, sincethis may re-introduce unwanted metal ionsremoved by M. oleifera). During the slow mixing,the fine particles and bacteria will begin to clumptogether and sink and settle to the bottom of thebucket.

6. Cover the bucket and leave it undisturbed until thewater becomes clear and the impurities have sunkto the bottom. This may take up to an hour.

7. The clean water may be siphoned or poured off thetop of the bucket or filtered through a clean cloth.The process removes at least 90% of the bacteriaand other impurities that cause turbidity.

Notes:

Both the seeds and the seed powder can be stored, butthe paste (made in step 4) should be freshly madeevery time water is to be purified.

For safety reasons, water purified in class must not beused as drinking water.

Cleaning water with moringa seeds

ness of the forming protein layer.How does this technique work?

When you see a layer of petrol on apuddle, you can see a variety of iri-descent colours: light bounces offboth the top and bottom of the petrollayer. The reflected light waves willbe slightly out of phase, and depend-ing on the thickness of the petrollayer, will either add up or canceleach other out, resulting in differentcolours. Many more materials are

DriedMoringaoleiferaseeds

Image courtesy of Dr Majority Kwaambwa

University of Botswana in Gaborone,Botswana, set out to investigate further (see Kwaambwa et al., 2010).They produced a purified extract ofall the water-soluble protein from theseeds to study how the proteinadsorbs onto an interface betweenwater and silica (silicon dioxide, SiO2)as a model for the interface betweenwater and mineral particles.

The team used a neutron beam atthe Institut Laue Langevinw2 inGrenoble, France, in a techniquecalled neutron reflectometry, to meas-ure the thickness, density and coarse-

M. oleifera seeds are groundto a powder before use

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The mother of moringa researcher Dr Kwaambwa demonstrates how theseeds are treated for water purification

Images courtesy of Dr Majority Kwaambwa, University of Botswana

transparent to neutrons than to light,and neutron wavelengths are alsoabout one thousand times shorter(0.2-2 nm) than those of light (about0.5 μm), which is why a neutron beamcan be used to measure layers of pro-tein a single molecule thick.

The ‘white’ neutron beam is shoneonto the sample, and reflectivity is

measured as a function of neutron‘colour’ (i.e. wavelength), telling sci-entists how many molecules thick thelayer is, how densely packed the mol-ecules are, and how rough the surfaceof the layer is.

In the M. oleifera experiment, thescientists found that the seed proteinforms dense layers thicker than a sin-gle molecule even at concentrations aslow as 0.025 wt% – so the binding isvery efficient. The surface of the lay-ers is remarkably smooth, but thearray of M. oleifera protein is not uni-form: further away from the silicasurface, the number of water mole-cules among the protein increases,which can be seen as a change in den-sity, as measured by neutron reflec-tion (see diagram, left).

This suggests that the clumping isso efficient because M. oleifera proteinhas a strong tendency to bind both tomineral surfaces and to other M.oleifera protein molecules, even atvery low protein concentrations, dueto hydrophobic regions and to the factthat, even when the overall protein iselectrically neutral, different sub-groups of opposite charge will beionised.

Work on M. oleifera proteins continues to develop a non-toxic,biodegradable water purificationtreatment for which materials areavailable locally and at a much lowercost than aluminium salts. Questionsbeing addressed include how muchseed protein is needed, whether otherproteins or biopolymers are suitable,and if other impurities in water, suchas natural detergents, affect the actionof the process.

Mathur welcomes the scientificscrutiny. “We feel that the moringatree is very important and needs to bebrought to the attention of scientists

who can do further research,” he says.“It is not widely known in theWestern world yet because it doesn’tgrow there.” In the future, the miracletree could live up to its name. “Themoringa could save millions of livesaround the world for years to come,”states Mathur. “I cannot emphasiseenough how important it is.”

ReferencesFolkard G, Sutherland J (2002)

Development of a naturally derivedcoagulant for water and wastewatertreatment. Water Science andTechnology: Water Supply 2(5-6): 89-94

Folkard G, Sutherland J, Shaw R(1999) Water clarification usingMoringa oleifera seed coagulant. InShaw, RJ (ed) Running Water: MoreTechnical Briefs on Health, Water andSanitation pp 109-112. Rugby, UK: ITPublications. ISBN: 9781853394508

Ghebremichael KA et al. (2005) A sim-ple purification and activity assayof the coagulant protein fromMoringa oleifera seed. Water Research39: 2338-2344. doi:10.1016/j.watres.2005.04.012

Kwaambwa HM, Hellsing M, RennieAR (2010) Adsorption of a watertreatment protein from Moringaoleifera seeds to a silicon oxide surface studied by neutron reflec-tion. Langmuir 26(6): 3902-3910. doi: 10.1021/la9031046

Mitchell WA et al. (2008) Science forthe Next Generation: activities forprimary school. Science in School 10:64-69.www.scienceinschool.org/2008/issue10/nextgeneration

Image courtesy of M

aja Hellsing

Closest to the silica surface, M. oleiferaprotein is packed very densely, in a layerabout two molecules thick (50 Å). Then,with increasing distance from the silicasurface, the concentration of adsorbedprotein decreases rapidly

50

40

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Moringa protein in the adsorbed layer [%]

Distance from silica surface [Å]

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The M. oleifera tree


Web referencesw1 – Trees for Life International pro-

vides an international forum onbeneficial trees and plants, and hasbeen promoting the moringa treefor many years, sending literatureand information to universities,embassies and heads of state, aswell as producing educationalmaterial for schools. See:www.treesforlife.org

w2 – To learn more about the InstitutLaue-Langevin, see: www.ill.eu

ResourcesIf you enjoyed reading this article,

take a look at other Science in Schoolarticles about research done at ILL.See: www.scienceinschool.org/ill

Sue Nelson is an award-winningUK science broadcaster and writer. Aphysics graduate, Sue also studiedspace science and astronomy at theUniversity of Michigan as a KnightWallace journalism fellow in 2002 andrecently completed a one-year NestaDream Time fellowship writing science-based dramas. Her reportshave appeared on all the BBC’snational TV and radio news bulletins.Co-author of the popular science book

How to Clone the Perfect Blonde, Suehas written for The Sunday Times, TheObserver, The Guardian and TheIndependent and has contributed opin-ion columns on science for The Times.


Section of amoringa pod

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BiologyGenetics Immune systemInsect developmentCell proliferationGeneral cytologyEnzyme pathwaysCancer researchAges 16+

This article demonstratesthat science never sleeps,shaking up the dogmathat uracil only exists inRNA. As the articleexplains, this is notalways the case. Andeven when it is, whyshould that be?

To help the studentsunderstand the article,guiding questions couldbe:

1. Describe the bondingstructures betweenthe two complemen-tary base pairs inDNA.

2. Which of the bases isreplaced in RNA?

3. Describe and draw agraph of the repairenzyme pathway trig-gered when uracil isfound in DNA.

4. The ratio of whichmolecules could beadjusted to stop can-cerous cells fromgrowing and dividing?

5. Why is uracil ‘tolerat-ed’ in RNA?

6. Which living organ-isms use uracil DNAand how?

Friedlinde Krotscheck,AustriaR

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Thymine versus uracilOur genetic information is stored in

the form of DNA, using a four-letteralphabet. The four ‘letters’ correspondto the four chemical bases that eachbuilding block of DNA – called anucleotide – can have: adenine (A),thymine (T), cytosine (C) and guanine(G; see Figure 1 on page 28). As JamesWatson and Francis Crick famously

discovered, DNA forms a doublehelix in which the four bases alwayspair up the same way, through specif-ic hydrogen bonds: adenine binds tothymine, and guanine to cytosine (seeFigures 2 and 3).

There is an alternative fifth letter,though: uracil (U), which forms thesame pattern of hydrogen bonds withadenine (see Figure 4). But although

Uracil in DNA:error or signal?Uracil is well known as one of the basesused in RNA, but why is it not used inDNA – or is it? Angéla Békési and BeátaG Vértessy investigate.

Endopterygotes such asants lack the enzymecapable of removinguracil from their DNA

Image courtesy of spxC

hrome / iStockphoto and N

icola Graf


Thymine (5-methyl uracil;

deamination

Hydrolytic

Guanine (G)

Cytosine (C) Uracil (U)

(A) Adenine T)


uracil is commonly used in RNA, thisis not the case in DNA, wherethymine is used instead. Why mightthis be?

Chemically, thymine is a uracil mol-ecule with an extra methyl groupattached. What would be the advan-tage, in evolutionary terms, of usingthis more complex building block inDNA? The answer may lie in howcells correct damage to DNA.

Cytosine can spontaneously turninto uracil, through a process called

hydrolytic deamination (see Figure 4).When this happens, the guanine thatwas initially bound to that cytosinemolecule is left opposite uracilinstead (remember that uracil normal-ly binds to adenine). When the cellnext replicates its DNA, the positionopposite this uracil molecule wouldbe taken up by an adenine instead ofthe guanine that should be there,altering the message that this sectionof DNA encodes (see Figure 5). Thisprocess of cytosine deamination is

one of the most common types ofDNA damage, but is normally cor-rected effectively. How does the celldo this?

Cells have a repair system that candetect when a uracil is sitting where acytosine should be, and correct themistake before it is replicated andpassed on. The complex machinery todo that consists of several enzymes:first uracil-DNA glycosylases recog-nise the uracil, and cut it out of theDNA. Then several enzymes con-tribute to the elimination and re-synthesis of the damaged part ofDNA, during which the abasic (‘emp-ty’) site in the DNA is replaced with acytosine (see Figure 6).

However, the most common form ofuracil-DNA glycosylase cannot tellwhich base the uracil is paired with,i.e. whether the uracil was intendedto be there (if bound with adenine) orif it is a mutated cytosine (and isopposite guanine); instead, it wouldrecognise and cut out both types ofuracil. Clearly, this would cause prob-

The chemical structure of DNA,showing the base-pairings A-T and G-C. The hydrogen-bondedbases link together the two sugar-phosphate backbones

Image courtesy of A

ngéla Békési

Image courtesy of N

icola Graf

Image courtesy of Forluvoft; im

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Image courtesy of M

adeleine Price Ball; im

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AdenineThymineCytosineGuanine

Sugar-phosphate backbone

AdenineThymine

CytosineGuanine

Phosphate-desoxyribosebackbone

OH Deoxyribose

Phosphate group

Organic basePA,T,G or C

O

Figure 2 Figure 3Figure 1

The key components of a nucleo -tide, the basic building block ofDNA. The sugar deoxyribose and thephosphate group are invariant,whereas the organic base can be ofone of four types: A, T, G and C

The double helix structure of DNA

Figure 4

Guanine and cytosine forma base pair stabilised bythree hydrogen bonds,whereas adenine andthymine bind to each otherthrough two hydrogenbonds. The red frames high-light the functional groups ofcytosine and thymine thatare responsible for formingthe hydrogen bonds.Cytosine can spontaneouslyundergo hydrolytic deamina-tion, resulting in a uracilbase with the same capabili-ty for hydrogen bond forma-tion as thymine

Image courtesy of taram

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lems. The solution to this potentialproblem is thought to have been theevolution of a mechanism in which‘correct’ uracils (paired with adenine)were labelled with a methyl group –resulting in thymine. This way, if thecell machinery found a uracil, it cut itout and repaired it, but if it found auracil with a methyl label – a thymine(see Figure 4) – it left it. Over time,therefore, thymine in DNA becamethe standard instead of uracil, andmost cells now use uracil only in RNA.

Why was uracil retained in RNA?RNA is more short-lived than DNAand – with a few exceptions – is notthe repository for long-term storageof genetic information, so cytosinemolecules that spontaneously turninto uracils in RNA do not present agreat threat to the cell. Thus, therewas probably no evolutionary pres-sure to replace uracil with the morecomplex (and presumably more cost-ly) thymine in RNA.

Thymine-less cell deathWhen DNA is synthesised, the

DNA polymerase enzymes (whichcatalyse the synthesis) cannot dis-criminate between thymine anduracil. They only check whether thehydrogen bonds form correctly, i.e.whether the base pairs are matchedproperly. To these enzymes, it doesnot matter whether thymine or uracilbinds to adenine. Normally, theamounts of deoxyuridine triphos-phate (dUTP, a source of uracil) in thecell are kept very low compared tolevels of deoxythymidine triphos-phate (dTTP, a thymine source), pre-venting uracil incorporation duringDNA synthesis.

If this strict regulation is perturbedand the ratio of dUTP to dTTP rises,the amount of uracil that is incorrectlyincorporated into DNA also increases.The repair system – which, unlikeDNA polymerases, can distinguishuracil from thymine – then attemptsto cut out the uracil with the help of uracil-DNA glycosylase and to re-synthesise the DNA, whichinvolves temporarily cleaving (cutting) the DNA backbone.However, if the ratio of dUTP todTTP is still elevated, this re-synthesismay again incorporate uracil insteadof thymine. This cycle eventuallyleads to DNA strand breaks and chro-mosome fragmentation, when thesetemporary cuts in the DNA happenone after the other and too close toeach other (see Figure 7). This resultsin a specific type of programmed celldeath, called thymine-less cell death.

The process of thymine-less celldeath can be deliberately exploited inthe treatment of cancer. Because can-cer cells proliferate at such a high ratecompared to normal cells, they syn-thesise a greater amount of DNA pergiven time period and thereforerequire large amounts of dUTP. Byraising the ratio of dUTP to dTTP,these cancer cells can be selectivelytargeted and eliminated.

Image courtesy of Angéla Békési

DNA polymerase

High dUTP:dTTP

DNA replication

DNA repair

Uracil-DNA glycosylase

U U U U

U

Chromosome fragmentation

Thymine-less cell death

U = Uracil

Image courtesy of N

icola Graf

Hydrolytic deamination

Uracil is replaced w

ith cytosinetranscription + translation

transcription + translation

Arginine is replaced by histidine

I-R-L

Next replication

5’ ATC – CGT – T TG 3’

3’ TAG – GCA – AAC 5’

5’ ATC – C GT – TTG 3’

3’ TAG – GUA – AAC 5’

5’ ATC – C AT – T TG 3’

3’ TAG – GUA – AAC 5’ I-H-L

x

x

Uracil-DNAglycosylasesremove U

Resynthesis andreinsertion ofcytosineabasic site

5’ ATC – C GT – TTG 3’


5’ ATC – C GT – T TG 3’


5’ ATC – C GT – T TG 3’

3’ TAG – G CA – AAC 5’

Figure 5 Figure 6

Hydrolytic deamination of cytosine canchange the amino acids encoded by thesequence

Repair of hydrolyticdeamination

Figure 7

If dUTP:dTTP increases, DNApolymerase frequently incor-porates uracil instead ofthymine during both replica-tion and repair. Uracil-DNAglycosylase removes the uraciland initiates further repairinvolving DNA strand breaksin an intermediate step. Repairsynthesis, however, may rein-troduce uracil, leading to afutile DNA repair cycle.Eventually, the system is over-loaded and chromosome frag-mentation occurs, leading tocell death


www.scienceinschool.org30

Uracil DNA still existsAlthough most cells use uracil for

RNA and thymine for DNA, there areexceptions. Some organisms haveuracil instead of thymine in all theirDNA, and other organisms haveuracil in only some of their DNA.What could be the evolutionaryadvantage of that? Let’s take a look at some examples.

Uracil in viral DNATwo species of phage (viruses that

infect bacteria) are known to haveDNA genomes with only uracil andno thymine. We do not yet knowwhether these phages are representa-tives of an ancient life form that neverevolved thymine DNA, or whethertheir uracil-substituted genomes are anewly evolved strategy. Nor do weknow why these phages use uracilinstead of thymine, but it may play anessential role in the life cycle of theseviruses. If that is the case, it wouldmake sense for the viruses to ensurethat the uracil in their DNA is notreplaced with thymine. And one ofthese phages has in fact been shownto have a gene that encodes a specificprotein to inhibit the host’s uracil-DNA glycosylase, thus preventing theviral genome from having its uracil‘repaired’ by the host enzymes.

Programmed cell death in insectlife cycles

Uracil-DNA also appears to play arole in the development of endoptery-gotes – insects that undergo pupationduring their life cycle (ants and but-

terflies do;grasshop-

pers andtermites

do not).These insects

lack the maingene for uracil-DNA

glycosylase, whichwould otherwiseremove uracil fromtheir DNA.

Beneficial errors: the vertebrateimmune system

Uracil in DNA, however, can alsobe found closer to home – in theimmune system of vertebrates like us.Part of our immune system, the adap-tive immune system, produces a largenumber of different antibodies thatare trained to protect us from specificpathogens. To increase the number ofdifferent antibodies that can be creat-ed, we shuffle the DNA sequence inthe regions that code for them, notonly by recombining the existingsequences in the cells but also by creating new ones through vastlyincreased mutation rates, known ashypermutation.

Hypermutation starts with a specificenzyme (an activation-induced deami-nase) that changes cytosine into uracil(see Figure 4) at specific DNA loci, elic-iting an error-prone repair response,which the organism uses to its advan-tage: ‘errors’ generate new sequencesthat can be used to make differentantibodies. This system is very strictlyregulated, however, as if it got out ofhand, it would lead to cancer.

Moreover, our own research hasshown that, in larvae of the fruit flyDrosophila melanogaster, the ratio ofdUTP to dTTP is regulated in anunusual manner: in all tissues thatwill not be needed in the adult insect,there are much lower levels of theenzyme that breaks down dUTP andgenerates a precursor for dTTP pro-duction. Consequently, significantamounts of uracil are incorporatedinto these tissues during DNA synthe-sis.

So during the larval stages, uracil-DNA is produced and seems not to becorrected in tissues that are to bedegraded during the pupal stage. Asthese insects lack the main uracil-DNA glycosylase enzyme, at thepupal stage, additional uracil-DNA-specific factors may recognise thisaccumulated uracil as a signal to initi-ate cell death. We have already identi-fied an insect-specific protein thatseems to be capable of degradinguracil-DNA, and we are investigatingwhether this enzyme is used to initi-ate programmed cell death.

Artist’s impression of a phage virus infecting a bacterial cell

Image courtesy of cdascher / iStockphoto


Image courtesy of taram

ol / iStockphoto




When considering the question ofwhy uracil or why thymine, we needto consider the evolutionary context.Living organisms have evolved in acontinuously changing environment,facing a dynamic set of challenges.Thus, a solution that avoids mistakesbeing incorporated into DNA isadvantageous to most organisms andmost cells, which explains whythymine-DNA became the norm.Under certain circumstances, howev-er, ‘mistakes’ themselves can be bene-ficial, which is why some cells stilluse uracil in their DNA.

ResourcesTo find out more about the work of

Beáta Vértessy’s research group,see: www.enzim.hu/~vertessy

To download a summary of VillőMuha’s PhD thesis, which was writ-ten under Beáta Vértessy’s supervi-sion and focuses on uracil-DNA inDrosophila melanogaster, use the link:http://teo.elte.hu/minosites/tezis2010_angol/v_muha.pdf

The complete thesis is available here:http://teo.elte.hu/minosites/ertekezes2010/muha_v.pdf

If you enjoyed reading this article,why not take a look at the full col-lection of biology-related articlespublished in Science in School? See:www.scienceinschool.org/biology

Angéla Békési was born 1977 inKaposvár, Hungary. In 2001, she grad-uated in chemistry from the EötvösLoránd University of Sciences, and intheology from the Pázmány PéterCatholic University (both inBudapest, Hungary), having joinedthe lab of Beáta Vértessy in 2000 as anundergraduate student. In 2001, shebegan a PhD on the regulation ofuracil-DNA repair and uracil process-ing in pupating insects. She identifieda new protein candidate for a noveltype of uracil-DNA sensor and

The presence of uracil in anti-body gene sequences elicits aDNA repair response, which hasthe effect of increasing antibodyprotein diversity. An extensiveantibody pool increases thechance of the immune systemrecognising unwanted invaders

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received her PhD in structural bio-chemistry from Eötvös LorándUniversity of Sciences in 2007. She iscontinuing her work as a postdoctoralscientist, and was a school ambassa-dor in the SET-Routes programme(www.set-routes.org/school/profiles/bekesi_en.html).

Beáta G Vértessy was born inBudapest, Hungary and was trainedin the biological sciences. She has anMSc from the University of Chicago,USA, a PhD / CSs from the EötvösLoránd University in Budapest,Hungary, and the HungarianAcademy of Sciences, and a DSc fromthe Hungarian Academy of Sciences.

Since 2000, she has been the head of alaboratory focusing on genomemetabolism and repair at the Instituteof Enzymology, Budapest, Hungary.The lab’s current research aims tounderstand the prevention, recogni-tion and repair of uracil in DNA fromthe perspectives of structural and cellbiology.



Flee, fight or freeze? For an ani-mal overcome with fear, that isthe essential question. The

answer often depends on the amyg-dala – a major emotion-processinghub nestled deep in the brain. In bothmice and humans, it affects how webehave in response to certain types offear, and helps to form long-termmemories of frightening experiences.However, very little is known abouthow cells in the amygdala communi-cate with other brain cells to producespecific fear-induced behaviours.

A recent study narrows this gap inknowledge, thanks to the innovativework of scientists at the EuropeanMolecular Biology Laboratoryw1

(EMBL) in Monterotondo, Italy, andGlaxoSmithKlinew2 in Verona, Italy.The scientists focused on one of manydifferent types of fear processed bythe amygdala. They used new tech-

When something frightens us, should wefreeze, or should we investigate? SarahStanley describes how scientists from theEuropean Molecular Biology Laboratoryare probing the mysteries of the brain,

seeking to understand our response to fear.

Cornelius Gross

A neural switch for fear


BL Photolab

Image courtesy of EMBL Photolab




niques to understand the interactionsbetween the areas of the braininvolved in reactions to that specifictype of fear. In the course of theirwork, they identified a switch thattoggles between two different fearresponses: freezing and, surprisingly,an alternative to the flee, fight orfreeze options, known as active riskassessment. This active responseinvolves behaviours like rearing, digging and exploring.

Mice conditioned to associate a tonewith an uncomfortable shock usuallyfreeze in fear upon hearing the sound,even if it is not accompanied by dis-comfort. Neurons called type 1 cells,which are found in the amygdala, are known to control the freezingresponse. When type 1 cells are pre-vented from sending signals to othercells, mice no longer freeze in fear.But, it seems, type 1 neurons are morethan just an on / off switch.

In a pioneering approach that usesboth pharmacology and genetics,EMBL scientists engineered mice sothat their type 1 cells could be turnedoff without disrupting other cells. Themice were made to produce certaindrug-sensitive proteins (receptors)exclusively in their type 1 cells. Whenthe mice were injected with the drug,it bound to those receptors, setting offchemical reactions that disrupted thecells’ electrical charge. Thus, theseneurons could no longer send electri-cal signals to surrounding brainregions.

Before treatment with the drug, themice had been conditioned to fear acertain tone. After their type 1 cellswere blocked, they were subjected tothe tone, and their behaviours wereobserved and analysed.

“When we inhibited these neurons,I was not surprised to see that themice stopped freezing, because [freezing] is what the amygdala wasthought to [control]. But we werevery surprised when they did a lot ofother things instead, like rearing andother risk-assessment behaviours,”

says Cornelius Gross, who led theresearch at EMBL. “It seemed that wewere not blocking the fear, but justchanging their responses from a pas-sive to an active coping strategy. Thatis not at all what this part of theamygdala was thought to do.”

To better understand the connec-tions between brain cells – the neuralcircuitry – involved in the switchfrom passive to active fear behav-iours, the scientists looked at activityin different brain regions using a typeof brain scan called functional mag-

netic resonance imaging (fMRI). Insmall animals like mice, fMRI meas-ures local blood volume as an indica-

BiologyGeneticsPharmacologyPhysiologyBehaviourAges 16+

In this article, several experiments are carried out with mice (inwhich both the behaviour and the activity of the brain wereanalysed) to understand the details of their response to fear. Suchresearch is very important to ultimatly improve our knowledgeabout how the human brain works.

This article can be extremely useful for giving students some insightinto how research is done in scientific laboratories. Teachers can gettheir students to read the article and then think about how respondto fear, perhaps even designing and performing an experiment.Furthermore, students can think about the evolutionary benefits ofthese reactions for our ancestors, and how useful they are in mod-ern life. Moreover, the students can try to find out about animalswith different responses to fear and try to relate their behaviour totheir environment.

The use of new research techniques such as pharmacogenetics andfunctional magnetic resonance imaging (fMRI) is also reported inthis article. Students aged 16 and over can try to find more informa-tion about how these techniques work and their importance inresearch.

Finally, this article could also be used as a starting point for dis-cussing research on animals. Students can think about how theresults obtained from animals can be applied to humans, and theycan also discuss alternatives to animal testing.

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Image courtesy of EMBL Photolab



tor of brain activity: the more bloodthere is in a particular area of thebrain, the more active those neuronsare. This study marks the first use offMRI to map neural circuitry in mice,using a new technique developed byGlaxoSmithKline scientist AngeloBifone and his team.

The brain scan yielded anotherunexpected result. Scientists previous-ly thought that the amygdala man-aged fear behaviours by simply relay-ing information to the brainstem,which links the brain to the spinalcord. But Cornelius, Angelo and theircolleagues found that in mice withblocked type 1 cells, the outer layer ofthe brain – the cortex – was highlyactive, indicating that it too plays arole in determining how mice react tofear. Activity was also observed in aregion of the brain called the choliner-gic basal forebrain, which is known toinfluence cortex activity.

Like all brain scans, fMRI requiresthe subject to remain very still, so itcan only be performed on mice thathave been anaesthetised. But the sci-entists wanted to confirm the associa-tion between the cortex and fearbehaviours in conscious mice. As theycould not observe brain activity whilethe mice were awake and therefore

external threats, the amygdala makesdecisions about how to respond.

It is important to note that the typeof fear explored in this study – condi-tioned fear of a painful shock – isvery specific. The results cannot nec-essarily be applied to behaviouralresponses to other types of fear inmice.

“There are multiple, parallel fearcircuits that handle different types offear information. For example, onepart of the [mouse] brain is often usedto process fear of a predator, such as acat, while another part usuallyresponds to aggressive behaviour byanother mouse,” Cornelius says. “Wethought there was a simplistic fearcircuit that is either on or off, but thatdoesn’t seem to be true.”

Also, scientists are not yet surewhether wild mice ever use riskassessment behaviours in response tothreatening stimuli. Blocking of type 1cells was performed artificially in thisstudy, and there may or may not besituations when the neurons wouldnaturally be inhibited, leading themouse to engage in investigativebehaviours to learn more about a per-ceived threat.

If the active response is found natu-rally in mice, what kinds of external

capable of displaying fear behaviour,the scientists took a differentapproach. They used the drugatropine to block cortex activity inmice whose type 1 cells were blocked,and found that the animals no longershowed any risk assessment behav-iours.

Thus, the scientists infer, the amyg-dala normally inhibits the cholinergicbasal forebrain, while it signals thebrainstem to control the passive fearresponse: freezing (see image above,A). When type 1 neurons are blocked,however, the amygdala releases itshold on the cholinergic basal fore-brain, leading to cortex activity andan active reaction to fear: risk assess-ment (see image on page 35, B).

“This is a powerful demonstrationof the ability of functional MRI toresolve brain circuits involved in com-plex tasks, like processing of emotionsand control of behavioural respons-es,” says Angelo, now at the ItalianInstitute of Technologyw3 in Pisa.

Taken together, the results of thearray of techniques used to explorethe freezing fear response in miceindicate that the amygdala plays amore complex role in fear processingthan previously thought. Instead ofmerely passing on information about

When mice hear a tone thatthey have been conditioned toassociate with an uncomfort-able shock, the amygdala isactivated and relays informationto the brainstem, making theanimal freeze (A).However, in mice in which type1 amygdala neurons have beenswitched off, these neurons nolonger suppress the surroundingtype 2 amygdala cells. Type 2neurons now activate the cortexvia the cholinergic basal fore-brain, blocking freezing andpromoting risk-assessmentinstead (B)

Image courtesy of Nicola Graf, Cornelius Gross and Marlene Rau

Cortex

Cholinergicbasal forebrainneurons

AmygdalaType 1 neurons activeType 2 neurons blocked

Brainstem

Freezingbehaviour

Conditioned tone

A




sensory cues are necessary to activateit? Previous studies have shown thatanimals located farther away from aperceived threat are more likely tofreeze in fear than run or fight. Butscientists cannot yet say whether useof an active risk assessment responseis a function of distance. Corneliusemphasises that it is important not toassume that risk assessment would beused in place of freezing in a situationperceived as less threatening.

Nonetheless, the study has signifi-cant implications. The pharmacoge-netic and fMRI techniques used bythe scientists will likely prove invalu-able in many other studies of neuralcircuits in mice. Indeed, Corneliusand his team have already used apharmacogenetic approach to revealcells that act as an input for anotherbrain region, the hippocampus, relay-ing information that enables a mouseto gauge an appropriate level of anxi-ety in an uncomfortable circumstance.

Furthermore, we humans also showfreezing and risk assessment respons-es to fear. We possess a region of theamygdala that is analogous to the onehousing the active / passive switch inmice. Patients who have sufferedlesions to this region are unable todevelop conditioned fear responses,

though they have normal reactions tofear in other situations. Thus, it islikely that the results of this studycould apply directly to humans,Cornelius says.

Though much remains to be discov-ered about how humans process fearin different situations, studying fearbrings scientists ever closer to devel-oping more effective treatments forfear-based illnesses – such as anxietydisorders and post-traumatic stressdisorder. In the words of two-timeNobel Prize-winning chemist MarieCurie, “Now is the time to under-stand more, so that we may fear less.”

ReferencesGozzi et al. (2010) A neural switch for

active and passive fear. Neuron67(4): 656-66. doi: 10.1016/j.neuron.2010.07.008

Web referencesw1 – To learn more about the

European Molecular BiologyLaboratory (EMBL), see:www.embl.org

w2 – For information aboutGlaxoSmithKline in Verona, Italy,see: www.gsk.it

w3 – To find out more about theItalian Institute of Technology, see:www.iit.it

ResourcesFor an introduction to the 2010 article

by Gozzi et al., see:

Pape HC (2010) Petrified or arousedwith fear: the central amygdalatakes the lead. Neuron 67(4): 527-529. doi: 10.1016/j.neuron.2010.08.009

As part of an exhibition (GooseBumps! The Science of Fear), theMuseum of Science, Boston, USA,devised some scary activities for theclassroom. See the museum's web-site (www.mos.org) or use the directlink: http://tinyurl.com/65savzz

For another example of research usingfMRI, see:

Hayes E (2010) The science ofhumour: Allan Reiss. Science inSchool 17: 8-10.www.scienceinschool.org/2010/issue17/allanreiss

If you enjoyed this article, you maylike to browse the other cutting-edge science articles in Science inSchool: www.scienceinschool.org/cuttingedge

Sarah Stanley graduated in biologyfrom the University of California,Santa Barbara, USA. At the time ofwriting this article, she was a sciencewriting intern at the EuropeanMolecular Biology Laboratory.Currently, she is an intern at DiscoverMagazine.


Cortex

Cholinergicbasal forebrainneurons

Brainstem

Risk assessmentbehaviour

Conditioned tone

AmygdalaType 1 neurons activeType 2 neurons blocked

B


BL Photolab



The resourcefulphysics teacherPhysics teacher Keith Gibbs shares some ofhis many demonstrations and experimentsfor the physics classroom.

During more than 30years of teachingphysics, I have come

across many interesting demon-strations and teaching ideas –often suggested by relatives,friends, colleagues and past stu-dents. In 2000, I began to gatherthese ideas together – this wasthe basis of the Schoolphysicswebsite and CD-ROM collection.Over time, I added more expla-nation and background for teach-ers whose specialism was notphysics.

Below are four ideas from thecollection. I hope that you willfind at least one of them new,challenging, informative and fun,and that the ideas go some waytowards popularising the subjectand making people realise thatphysics can be interesting andfun.

Boiling water under reducedpressureAge range: 13-15

This simple experimentdemonstrates that the saturatedvapour pressure of waterdepends on the temperature. It isbest performed as a teacherdemonstration, with a safetyscreen between the apparatusand the students.

Materials

· A round-bottomed flask

· A bung with two holes

· A glass tube, with an externaldiameter to fit the hole in thebung

· A rubber tube with a diameterto connect to the glass tube

· A thermometer to fit the holein the bung

· A Bunsen burner

· A retort stand and clamp

· A safety screen

· A tray

· Water

Procedure1. Fit the rubber tube onto the

end of the glass tube.2. Fit the thermometer and glass

tube into the holes in thebung, pour cold water into theflask until it is just less thanhalf full. Then seal the flaskwith the bung.

3. Fit the clamp onto the rubbertube but do not close theclamp.

Image courtesy of aristotoo / iStockphoto


Teaching activities


See also the general safety note onthe Science in School website(www.scienceinschool.org/safety)and on page 65.

TheoryThe explanation is that the saturat-

ed vapour pressure of water dependson the temperature: the lower thetemperature, the less water vapourthe air can hold (see Table 1). Whenthe water condenses, it lowers thepressure in the flask – and this, ofcourse, allows water to boil at lessthan 100 °C.

An alternative methodA simpler method is to partly fill

(about 20%) a syringe with 50-60 °Cwarm water. Then pull on the plungerof the syringe. This lowers the pres-sure in the syringe, causing the waterto boil at well below 100 °C.

PhysicsChemistryThermodynamicsCircular motionElectromagnetismGravitational fieldsInertiaBoiling pointsAges 13-19

The four experiments described in this article areinnovative and use items that are easily available inschool laboratories. The aim, materials, procedure anddiagram for each experiment make it very straightfor-ward for teachers and students to understand theprocesses and theories involved. It is also interestingto read about the author’s experiences and the resultsthat he obtained from these experiments.

Teachers could use the experiments for a wide array ofphysics topics and adapt them to different age groups,depending on how much theory the teacher choosesto explain. They can be performed as a pre-topicexperiment to introduce the students to the theory or

else while the theory is being explained, to consoli-date concepts with facts. A discussion can be heldwith students during the experimental investigationsto prompt them to make predictions and explain theoutcomes.

The activities can be used with students of differentages, depending on the emphasis. The boiling wateractivity could be used with students aged 13-15 to dis-cuss the boiling point of water; for students aged 16-19, it could be used in a lesson about gas laws. Thecoat-hanger experiments could be used with 16- to18-year-olds to introduce circular motion, centripetalforce and centripetal acceleration. For 10- to 13-year-olds, the electromagnetic separator activity could beused in general science lessons or to discuss magnet-ic materials; for students aged 14+, it could be used inmagnetism lessons. Finally, the experiment with thefalling jar could be used for students aged 16+ to teachsimple harmonic motion, gravitation and inertia.

These types of demonstration are ideal for studentswho are visual learners and who will understand andremember theory better when they see it applied inpractice.

Catherine Cutajar, MaltaRE

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4. Use the Bunsen burner to heat thewater to boiling.

5. Close the clamp and turn off theBunsen burner.

6. Invert the flask and pour coldwater over it.

Steam will condense inside theflask, reducing the pressure andallowing the water to start boilingagain. When the water stops boiling,pour more water over the flask. Howlow can you get the temperature andstill observe the water boiling? Youshould be able to get the water to boilat 40 °C – I once observed the waterboiling at body temperature (37 °C)!

Safety note: wear safely goggles.Although unlikely, it is possible thatthe glass flask could shatter, so keep asafety screen between the experi-ments and the students. If possible,stand behind the screen yourself.

Image courtesy of Keith G

ibbs

Table 1: Dependence of saturated vapourpressure of water on temperature

Temperature Saturated vapour pressure

37 °C 0.06 x 105 Pa

60 °C 0.19 x 105 Pa

75 °C 0.38 x 105 Pa

85 °C 0.57 x 105 Pa

100 °C 105 Pa



The wire coat hanger and circular motionAge range: 14-18

This is a simple demonstration ofcentripetal force.

Materials· A wire coat hanger with the end

filed to a point

· A metal file

· A small coin

Procedure1. Bend the wire coat hanger until it

forms a square.2. File the tip of the hook flat and

then bend the hook until it pointstowards the opposite corner of thesquare (see diagram).

3. Balance a small coin (try a UK one-penny piece or a 5 or 10 Euro-cent coin) on the hook.

4. Place one finger in the corner of thesquare opposite the hook and spinthe coat hanger in a vertical circle.The coin should remain in place.

TheoryThe force of the hook on the coin

provides the centripetal force, andthis always acts towards the centre ofrotation.

How many coins can you balanceon the swinging coat hanger? Myrecord is five one-penny pieces. Withonly one penny and with great care, Ihave once even been able to bring thecoat hanger to rest without the coinfalling off.

Electromagnetic separatorAge range: 16-18

This is a small-scale simulation ofthe type of electromagnetic separatorthat is used industrially to separatenon-ferrous metals from other non-metallic scrap, and is suitable as ateacher demonstration.

Materials· A U-shaped electromagnet with an

iron core to give a high field inten-sity

· An AC (alternating current) powersupply

· Aluminium scraps (e.g. kitchen foil)

· A piece of thin card

· Some scraps of paper

Procedure1. Place the card on top of one arm of

the electromagnet and put a fewscraps of aluminium and paperonto the card.

2. Connect the electromagnet to anAC supply and turn on the current.The aluminium scraps will be eject-ed from the magnetic field.

TheoryThe AC electromagnet induces

eddy currents within the aluminiumscraps. These turn the scraps into tinyelectromagnets that are then repelledby the large electromagnet and so flyoff the card. With non-metallic scrapsthere are no induced currents and sothese scraps remain on the card.

In a moving-belt version of thisexperiment, mixed metal and non-metal scraps are passed along a beltover an AC electromagnet. Thisinduces eddy currents in the metalscraps, which are then repelled by thefield and fly off sideways while theremaining non-metal scraps continuealong the belt. Schools might be ableto construct such a version fordemonstration use, using a mixture ofpaper and aluminium.

A floating block in a falling jarAge range: 11-18, depending on thetreatment of the theory.

This is a very useful demonstrationof one of the ideas of general relativi-ty, using a wooden block floating in ajar of water that is suspended from aspring.

Fairground ride-goersshould be grateful tocentripetal force

Image courtesy of Floortje / iStockphoto


Image courtesy of inabeanpod; image

source: Flickr


ibbs


ibbs


Teaching activities


Materials· A helical spring tied with string

to a plastic jar

· A wooden block or straw loadedwith modelling clay (e.g. Plasticine®)

· Water

Procedure1. Half fill the jar with water, add the

wooden block or straw, and sus-pend the apparatus from thespring.

2. Support the jar, then let it fall, sus-pended from the spring. The jarand contents will then oscillate in avertical plane (up and down) butthe water level will stay at thesame position in the jar and theblock or straw will float at thesame level in the water as it fallsand rises.

TheoryThe depth at which the wooden

block or straw floats depends on bothits weight (not its mass) and theupthrust on it. The upthrust dependson the weight of water displaced.Thus, as the acceleration of the jarand the block changes, the weight ofthe block and the upthrust on itchange in direct proportion to eachother; as a result, the depth at whichthe block floats remains unchanged asthe apparatus oscillates.

Objects undergoing accelerationbehave in the same way as theywould in a gravitational field. As thejar and its contents oscillate, theyhave an acceleration that is due to

both the constantgravitational fieldof Earth and thesimple harmonicmotion of theoscillation.

As the jarmoves upwards,its net accelera-tion is greaterthan that ofEarth’s gravita-tional field and as

it falls, its acceleration is less than thatof Earth’s field. On the downwardpart of the motion, it is as if the jarwere on the Moon, where the gravita-tional acceleration is less than onEarth.

This is a very useful demonstrationof the equivalence of gravitationaland inertial fields.

AcknowledgementsThe editors of Science in School

would like to thank Catherine Cutajarand Gerd Vogt for their help in select-ing the experiments to include in thisarticle.

Web referencew1 – To view more (free) teaching

material collected by Keith Gibbs orto purchase the CD-ROMs, see:www.schoolphysics.co.uk

ResourcesIf you enjoyed this article, you

might like to browse the rest of theteaching activities on the Science inSchool website. See:www.scienceinschool.org/teaching

If you prefer to concentrate onphysics, here is a list of all physics-related articles in Science in School:www.scienceinschool.org/physics

After graduating from UniversityCollege London, UK, with a degree inphysics, Keith Gibbs took a PGCEteacher training course at CambridgeUniversity, UK. He subsequentlytaught physics in four differentschools across the UK for 36 years,retiring in 2002.

The ideas in this article are just afew of more than 700 ideas and exper-iments that Keith Gibbs has collectedand devised over the years, availableon CD-ROM (currently £10). These, aswell as explanations suitable for 11- to 19-year-old students, anima-tions, lesson plans, images and muchmore, are available on a further CD-ROM which, once bought (currently£35), can be copied within the schooland made available via the school’sintranet. See the Schoolphysics web-sitew1.

Keith has written and contributedto a number of physics textbooks.Recently, he has worked with PearsonEducation on animations foradvanced-level physics courses, andpractical projects for younger physicsstudents.

Keith also travels extensively,demonstrating his collection of exper-iments. If you are interested in a visit,contact him via the Schoolphysicswebsitew1.

Artist’s impression of a large electromag-net, of the type used for separation in anindustrial setting

Image courtesy of ZargonDesign / iStockphoto

Computer-simulated image of the nightsky, were it to feature a black hole with amass ten times that of the Sun, and seenfrom a distance of 600 km. Einstein’s the-ory of general relativity allows details ofa black hole’s structure to be calculated.Black holes are thought to be distortionsin space and time, consisting of zero vol-ume and infinite density.

Image courtesy of U

te Kraus; im

age source: Wikim

edia Com

mons



ibbs



BiologyAges 10-15

As a secondary-school biology teacher I had nevercome across the idea of teaching genetics usingmythical creatures, but after my initial surprise, Irealised that using the genetics of dragons was per-fectly coherent with the scientific facts... and reallygood fun! The idea of randomly choosing genes andlooking for the resulting traits of baby dragons isingenious and effective at the same time.

Even if they aren’t real, dragons can help to raiseinterest in a topic generally considered boring (atleast by students) and can convey scientific conceptsas well as real organisms like Mendel’s peas do.

I recommend this article to primary- and lower-sec-ondary school biology teachers willing to address thebasics of Mendelian genetics (genes, alleles, geno-

type and phenotype, dominance, meiosis and breed-ing) in a novel and playful way. The activity could becarried out very easily in the classroom with practi-cally no equipment.

Suitable comprehension questions include:

1) Dragons have:

a) seven chromosomes

b) seven genes

c) seven pair of chromosomes

d) seven alleles.

2) When you breed dragons, the number of chromo-somes of their offspring:

a) is divided into half

b) remains the same

c) is doubled

d) depends on their sex.

Giulia Realdon, ItalyRE

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Breeding dragons:investigatingMendelian inheritanceMendelian inheritance canbe a tricky topic to teach, butPat Tellinghuisen, JenniferSexton and Rachel Shevin’smemorable dragon-breedinggame makes it easier tounderstand and remember.

Image courtesy of julos / iStockphoto

Image courtesy of Alexsey / iStockphoto


Teaching activities


Dragons may be mythical ani-mals, but they can still begood tools for investigating

Mendelian inheritance. In the follow-ing activity, students will ‘breed’ babydragons, using paper chromosomes todetermine the genotype and pheno-type.

The activity has been tested withstudents aged 12-13, and generallytakes one lesson – about 45 to 60 min-utes.

Materials

For the whole class

· A DNA model

· A picture of a chromosome

For each student

· A set of chromosome strips in twocolours (14 pink strips for themother and 14 blue strips for thefather)

· A student worksheet

· Crayons (at least four colours)

The chromosome strips, Tables 1-3from the worksheet and the basicdragon drawing can be found onpages 42/43 or downloaded from theScience in School websitew1.

ProcedureUsing the information below, intro-

duce the dragon story and therequired background for the activity tothe students. Then hand out the mate-rials and let the students follow theinstructions on the student worksheet.Tables 1–3 can also be downloadedfrom the Science in School websitew1.

The storyDragons are a curious type of crea-

ture. Amazingly, though, their genet-ics is very similar to that of humans –or even guinea pigs. Many schoolskeep pet guinea pigs, but wouldn’t itbe much more exciting to keep a herdof dragons? Unfortunately, dragonsare very expensive, so your schoolcan only afford two – one of each sex.The purpose of this activity is todetermine what kinds of dragon you

could have in your herd when (or if)your two dragons decide to mate.

Background for the studentsEach cell in all living organisms

contains hereditary information thatis encoded by a molecule calleddeoxyribonucleic acid (DNA): showstudents the DNA model. DNA is anextremely long and skinny molecule,which when all coiled up andbunched together, is called a chromo-some: show students the picture of achromosome. Each chromosome is aseparate piece of DNA, so a cell witheight chromosomes has eight longpieces of DNA.

A gene is a segment of the longDNA molecule. Different genes maybe different lengths and each gene is acode for how a certain polypeptideshould be made. One or morepolypeptides form a protein, whichcan generally be sorted into two dif-ferent types: those that run the chemi-cal reactions in your body (enzymes),and those that are the structural com-ponents of your body (structural pro-teins). How an organism looks andfunctions is a result of the cumulativeeffect of both these types of protein.

Any organism that has ‘parents’ hasan even number of chromosomes,because half of the chromosomescome from the ‘father’ and the other

half from the ‘mother’. For example,in plants, a pollen grain is the pater-nal contribution and an ovule is thematernal contribution. These two cellscombine to make a single cell, whichwill grow into a seed (the offspring).

Humans have 46 chromosomes,sorted into 23 pairs. One chromosomein each of the 23 pairs is from the per-son’s father, the other from his or hermother. Since chromosomes come inpairs, genes do too. One gene is locat-ed on one member of the chromo-some pair; the other gene is in thesame location on the other chromo-some. The gene ‘pair’ is technicallyreferred to as a ‘gene’, as both mem-bers of the pair encode the same trait.For any gene, a variety of differentforms – known as alleles – may exist,but each person can have a maximumof only two alleles (one from themother, and one from the father). Thetwo copies of the gene that a personhas may be the same or different alle-les.

Our dragons have 14 chromosomesin seven pairs, and we will look atonly one gene on each of the pairs.We will be investigating seven differ-ent traits (e.g. the ability to breathefire), each of which is controlled by asingle gene – we say that such a traitis monogenic. Each of the seven geneshas two alleles.

How DNA is packaged intochromosomes (not to scale)

DeoxyribonucleicAcid (DNA)

A gene

Chromosome

Image courtesy of N

icola Graf

Different alleles of the samegene (not to scale)

Image courtesy of Darryl Leja, NHGRI / NIH

A a



One set of 14 strips represents the chromosomes fromthe mother (female) dragon. The other, differentlycoloured set, represents the chromosomes from the father(male) dragon.

Each chromosome strip has a letter, which may be eitherupper or lower case. The upper-case letters representdominant alleles, and the lower-case letters representrecessive alleles. Each pair of letters codes for a trait. If atleast one dominant allele (upper-case letter) is present, thedominant trait will occur (e.g. the dragon can breathe fire);the recessive trait (e.g. inability to breathe fire) will onlyoccur if the dragon has two copies of the recessive allele.1. Sort the chromosomes so that they are matched into

pairs of the same length and letter of the alphabet. Youshould have seven chromosome pairs for each colour(blue for male, pink for female).The traits encoded by the letters are as follows:

· F and f represent whether or not the dragon breathes fire

· M and m represent the number of toes· S and s represent the number of tail spikes· T and t represent the colour of the tail· A and a represent the colour of the body· W and w represent the colour of the wings· H and h represent whether or not the dragon has a

horn.2. Take the longest pair of male chromosomes (blue) and

the longest pair of female chromosomes (pink) andplace them face down on your desk so that you cannotsee the letters.

3. Without turning the chromosomes over, pick one ofeach colour and put them together to form the chromo-some pair for the baby dragon. Discard the remainingpair of chromosomes.

4. Repeat steps 2 and 3, moving from the longest to theshortest chromosomes, until you have seven new chro-mosome pairs, each consisting of one pink and oneblue strip.

5. Turn over the seven pairs of chromosomes of the newbaby dragon. For each pair, record the letter on the bluechromosome in the ‘Male gene’ column in Table 1 andthe letter of the pink chromosome in the ‘Female gene’column. Be sure you copy the letters exactly, notingwhether they are upper or lower case.

6. Return all the chromosomes to their proper bags.

7. Record which alleles (letters) your dragon has for eachtrait, and enter them in the second column of Table 2.We refer to the two alleles inherited for a particulargene as the genotype (e.g. TT). The observable traits ofan individual (e.g. a red tail) are known as the phenotype.

8. Refer to Table 3 to determine which alleles are domi-nant or recessive for each trait, then enter the pheno-type of your dragon in Table 2.

9. Now you are ready to draw your baby dragon: colourand add the relevant body parts to the basic dragonpicture (which can also be downloaded from the Sciencein School websitew1). See Table 3 for suggestions as tohow the additional body parts can be drawn.

A

H

W

T

S

M

F

a

h

w

t

s

m

f

A

H

W

T

S

M

F

a

h

w

t

s

m

f

Student worksheet


Genotype Phenotype

FF or Ff Breathes fire

ff Does not breathe fire

MM or Mm Four toes

mm Three toes (all dragons have at least three toes)

SS or Ss Five spikes on tail

ss Four spikes on tail (all dragons have at least four tail spikes)

TT or Tt Red tail

tt Yellow tail

WW or Ww Red wings

ww Yellow wings

HH or Hh Horn

hh No horn

AA or Aa Blue body and head

aa Green body and head

Table 3: Translating the dragon genotype into the phenotype

Teaching activities


Table 1: The genes your dragonhas inherited from its parents

Trait Genotype Phenotype

Fire/No fire (F/f)

Toes (M/m)

Spikes on tail (S/s)

Tail colour (T/t)

Wing colour (W/w)

Horn/no horn (H/h)

Body colour (A/a)

Table 2: Genotype and phenotype of your baby dragon

Male gene Female gene(blue) (pink)

The basic dragonpicture


Trait Genotype Phenotype

Body colour (A/Ä/a)

Variations

CodominanceTo introduce the concept of codomi-

nance, you can extend the activity byswapping the relevant materials con-cerning the body colour trait (geno-type Aa) for the following ones withthe genotypes A/Ä/a, where A and Äare codominant and a is recessive:

Genotype Phenotype

AA or Aa Blue body and head

ÄÄ or Äa Black body and head

AÄ Stripy blue and black body and head

aa White body and head

Table 1a: Translating the dragon genotypeinto the phenotype (extension for codom-inance example)

AcknowledgementsThis activity is based on an idea by

Patti Soderberg, adapted with permis-sion from The Science Teacher (seeSoderberg, 1992). Her reebops lessonwas then adapted by the authors.Credit for the chromosome strips goesto Nancy Clarkw2, and Marlene Rau,editor of Science in School, includedthe codominance example.

References

Soderberg P (1992) Marshmallowmeiosis. The Science Teacher 59(8): 28-31. The article can be freely down-loaded from the Science in School web-site, with kind permission from TheScience Teacher. See:www.scienceinschool.org/2011/issue18/dragons#resources

Web referencesw1 – The chromosome strips, tables

and the basic picture for this activi-ty can be downloaded from theScience in School website. See:www.scienceinschool.org/2011/issue18/dragons#resources

w2 – Retired US science teacherNancy Clark’s collection of class-room resources can be found online:www.nclark.net

w3 – Find out more about theVanderbilt Student Volunteers forScience here: http://studentorgs.vanderbilt.edu/vsvs

ResourcesThe Scottish ‘Gene jury’ project pro-

poses a ‘make a baby’ game, focus-ing on pre-implantation diagnosticsand genetics. See the Gene jurywebsite (www.biology.ed.ac.uk/projects/GeneJury) or use the directlink: http://tinyurl.com/6edlhnq

To learn more about genetic diseases,and the research into them, see:

Patterson L (2009) Getting a grip ongenetic diseases. Science in School 13:

53-58. www.scienceinschool.org/2009/issue13/insight

For our two-part article on molecularevolution and the genetics behindpositive selection of certain alleles,see:

Bryk J (2010) Natural selection atthe molecular level. Science in School14: 58-62. www.scienceinschool.org/2010/issue14/evolution

Bryk J (2010) Human evolution:testing the molecular basis. Sciencein School 17: 11-16.www.scienceinschool.org/2010/issue17/evolution

Staying with the subject of geneticsand evolution, a simple way toteach the Hardy-Weinberg principlein class is described here:

Pongsophon P et al. (2007)Counting Buttons: demonstratingthe Hardy-Weinberg principle.Science in School 6: 30-35.www.scienceinschool.org/2007/issue6/hardyweinberg

Try the UK Science museum’s onlinegame ‘Thingdom’ to learn aboutgenetics while creating your ownfictional organism. See:www.sciencemuseum.org.uk/WhoAmI/Thingdom.aspx

If you enjoyed this article, why notbrowse our full collection of biologyarticles? See:www.scienceinschool.org/biology

Patricia Tellinghuisen is the Directorof the Vanderbilt Student Volunteersfor Science (VSVS)w3 and FacultyAdvisor at Vanderbilt University,Nashville, Tennessee, USA. JenniferSexton and Rachel Shevin wereundergraduate laboratory assistantsat the VSVS.


Table 2a: Genotype and phenotype ofyour baby dragon (extension for codomi-nance example)


Chromosome set 1

For the father

For the mother

Chromosome set 2

For the father

For the mother

Other variationsInstead of drawing dragon parts,

you could have your students drawother mythical creatures, or evenbuild them, for example from marsh

A Ä

A Ä

A A

a Ä



Heater mealsHeater meals – originally developed

for military use – are ready-made self-heating meal packs. They can be heat-ed in many ways – by pressing a but-ton on the packaging, unwrappingand shaking the pack, or pouring thecontents of one bag into another andwaiting for a few minutes – all ofwhich use exothermic chemical reac-tions. These meals can be used to moti-vate students to study such reactionsrelatively safely and without the use ofa burner. Plus there is the added valueof discussing the negative ecologicalaspects of disposable meals.

For the following experiment, weuse the Crosse & Blackwell heater-

meal system, which relies on the reac-tion of magnesium and salt water toproduce hydrogen:Mg (s) + 2H2O (l) -> Mg2+ (aq) + H2 (g)�

+ 2OH- (aq)s: solid; l: liquid; g: gaseous; aq: insolution; the vertical arrow indicatesthat gas is released.

This reaction is very slow, due topassivation, so to speed it up, ironand salt are added. Passivation is theprocess by which a material is madeless reactive, usually by the deposi-tion of a layer of oxide on its surface:if you place a strip of magnesium intocold water, its surface will oxidise tomagnesium hydroxide (Mg(OH)2),and this coating will prevent furtherreaction.

Therefore, in the heater meal, iron isadded to the magnesium, leading tothe production of a local cell – small-scale corrosion that happens wheretwo metals of different reactivity arein contact under humid conditions –which speeds up the exothermic reac-tion. Because the electron potential ofmagnesium is lower than that of iron(the less reactive metal), electrons willpass from the magnesium to the iron,and only from there into the water.Although magnesium cations (Mg2+)and hydroxide anions (OH-) continueto be formed, they are separated bythe iron and cannot combine to formmagnesium hydroxide. As a result,the magnesium does not become pas-sivated by a coating of magnesium

The heat is on: heating food and drinks with chemical energyHave you ever longed for a hotdrink or meal but had no fire orstove to hand? Marlene Raupresents two activities from the Lebensnaher Chemie-unterricht portal that use chemical reactions to heat food – and to introduce the topic of exothermic reactions.

Image courtesy of Martin Müller / pixelio


Science education projects


hydroxide, which would lower thereactivity.

Because the differently chargedmagnesium and hydroxide ions aremobile, in pure water they wouldsoon form magnesium hydroxide, thecharge would be equilibrated and thereaction would slow down again. Toprevent this, sodium chloride isadded to the water, so that the sodi-um (Na+) and chloride (Cl-) ions fromthe salt can move to the magnesiumand hydroxide ions instead, equili-brating the charge.

The experiment can be used tointroduce and discuss the topics ofelectron transfer, local cell, passiva-tion, sacrificial anodes, corrosion andthe composition of water (covalentbonds, polarity and oxidation num-bers). It takes about 45 minutes plusdiscussion time and has been success-fully tested with 14-year-olds to studyelectron transfer reactions and corro-sion, as well as with older students towork on electrochemistry.

Materials

Demonstration materials

· A magnesium strip

· Cold (unheated) saturated sodiumchloride solution (salt water)

· Phenolphthalein solution

· A Crosse & Blackwell heater-mealpack (available from a range ofsuppliers)w1

· A heat-resistant glass

· A laboratory thermometer

Materials per group

· An empty tea bag

· A small amount (a few grains, cov-ering the tip of a spatula) of themagnesium / iron powder mixturetaken from a Crosse & Blackwellheater-meal pack. Mixing magne-sium and iron powder yourselftends not to work since it is alreadypartly oxidised. The powder mix-ture in the heater meal packs isvacuum-sealed.

· A 50 ml syringe

· 10 ml saturated sodium chloridesolution

· A 20 ml syringe

· A three-way stopcock

· A small beaker

· A plastic tube fitting on the valvesof the stopcock (about 10 cm long)

· A bowl filled with water

· A burning candle

· A test tube

· Phenolphthalein solution <1% perweight

ChemistryGeneral scienceEnergyAges 8-19

This article allows students to discover the link between classroomscience and the real world. With experiments that have a wow fac-tor – often missing from practical lessons – students can developand build skills and knowledge.

The main subject addressed is chemistry, but the teacher couldadapt the lesson to include discussions of energy from other sub-jects, for example keeping warm, survival in cold climates, andtreatment of sports injuries. The experiments could also be used totrigger a discussion of how science works.

Nick Parmar, UKRE

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The heater-meal pack: the meal (silver bag), heater bag into which the meal is placed (orange), salt-waterbag (see-through), magnesium/iron mixture (white bag, taken out of the orange bag), spoon

Images courtesy of Gregor von Borstel



The plastic materials required for the experiment canbe ordered as part of the ChemZw2 kits, which weredeveloped in collaboration with the LebensnaherChemieunterricht (LNCU)w3 project, but are also availablefrom most medical and chemical lab suppliers.

Procedure1. Show a film about the heater mealw4.

2. Show the heater meal to the students.

3. Pour the contents of the heater-meal pack into a heat-resistant glass with a thermometer and observe thereaction – it heats up and bubbles are produced.

Note: if you use the contents of only two of the fourpackages of magnesium / iron mixture, you can savethe contents of the other two for the students’ experi-ments – it will be sufficient for about 20 studentgroups. Even with only two of the packages for thedemonstration, the heater meal will reach a tempera-ture of 100 °C after about one minute.

4. Discuss: why does this work? What is happening?What kind of gas is produced?

5. Explain the reaction of magnesium – ignore the ironand salt for the moment.

6. Demonstrate that a magnesium strip shows a weakreaction with cold saturated salt solution (which iswhat is added in the heater meal): a few gas bubblesare visible, and adding a droplet of phenolphthaleinsolution gives a light pink colour.

7. Before starting, demonstrate how to perform the oxy-hydrogen test: hold the top of a test tube close to aflame, allowing the gas in the tube to combust. Thereare two possible positive results:

a) If the tube contains both hydrogen and oxygen, thehydrogen will combust with a ‘squeaky pop’. Undernormal lab conditions, this is the usual result, as thetube will also contain oxygen from the air.

b) If the tube is completely filled with hydrogen, therewill be no sound, but the gas combusts with colour-less flame and the resulting water will fog the testtube. Furthermore, the exothermic reaction will heatthe tube. Students often mistake this for a negativeresult (no hydrogen).

8. Place the students into groups of three to perform theheater-meal experiment. Because of the resulting heat,the reaction speeds up, so should only be performedon a small scale (as suggested).

At the local cell, magnesium hydroxide is produced. Ifdesired, this can be detected using phenolphthalein(see below).

9. Hand out the worksheet (see page 49 or download itfrom the Science in School websitew5) describing how tocarry out the heater-meal experiment. The studentswill now be ready to start.

A closed and an open three-way stopcock

Images courtesy of Gregor von Borstel




Safety note: Wear safety goggles. The reaction createshighly flammable gas – be careful. See also the generalsafety note on the Science in School website(www.scienceinschool.org/safety) and on page 65.

1. Put the metal powder mixture into an empty tea bagand stuff this into a 50 ml syringe (without the tea bag,the powder could block the syringe). Press out the air.

2. Fill the 20 ml syringe with salt water and connect it tothe large syringe using a three-way stopcock.

3. Turn the stopcock’s valve to let the two materials flowtogether in the closed system.

As the reaction proceeds, gas will collect in one of thesyringes.

4. As soon as more than 25 ml of gas has collected, openthe stopcock and let the salt water flow out, collecting itin a beaker.

Safety note: because of the resulting heat, the reactionspeeds up (chain reaction). Keep a careful eye on it, tomake sure you let the water out of the syringe before

the gas that is produced pushes the piston out of thesyringe.

5. Once you have released the water, close the valve tokeep the gas in the syringe, and attach the plastic tubeto the valve. If gas continues to be produced, leave thevalve open.

6. Press the piston of the syringe to push the gas into atest tube through a pneumatic trough (use the plastictube, bowl of water and test tube as in the diagram).

7. Perform the test for hydrogen by holding the mouth ofthe test tube in a flame (see diagram below), makingsure you hold the top of the tube close enough to theflame. The test should be positive.

Optional: add one droplet of phenolphthalein solution tothe water you collected in the beaker. What happens?Why?

Health and safety note: the remaining liquids can bedisposed of in the sink. Clean the plastic materials withwater and leave them to dry.

Mixing the two liquidsvia the three-way stop-cock

Performing theoxyhydrogen test

Images courtesy of G

regor von Borstel

Collecting the gas

Student worksheet


1. Using the materials provided, how can you achieve the highest possible temperature change when making coffee?

You have 5 minutes to discuss your experimental approach in thegroup. Before you put your plan into action, check the safety (not thefeasibility) of it with your teacher.

You then have 10 minutes to perform the experiment. If you want tochange your procedure part way through, check with your teacher.

2. Before you start, record the starting temperature of the air and the coffee, and note the amount of coffee (in ml) you are making.

3. During the experiment, measure the air and coffee temperatures andnote down the maximum temperature you achieve.

Safety note: Wear safety goggles; do not drink the coffee.


DiscussionOther reactions commonly used in

heater meals include the oxidisationof iron, the reaction of anhydrous cal-cium chloride with water (see below)or, for cooling, the reaction of ammo-nium nitrate fertiliser with water.

Further experiments such as mak-ing your own heat and cold packs, ordetermining the oxygen content in theair with the aid of the iron oxidationreaction used in heat packs, aredescribed on the LNCU websitew3.

This activity can also form part of alesson in which the students developa script for a TV science programmeto answer a viewer’s question on thefunction of heater meals. The Englishversion of this worksheet is availableon the Science in School websitew5, theGerman one on the LNCU websitew3.

A quick cup of hot coffeeIn this activity, students heat coffee

using anhydrous calcium chlorideand water. The activity works well aspart of a teaching unit on dissolvingsalts in water, to introduce the ener-getic aspects of this process. Studentsshould already be familiar with ionicand covalent bonds. The activityworks well with groups of three stu-dents aged 14 and over.

One possibility is to discuss latticeenergy, using as an example fromeveryday life cold packs that rely onan endothermic reaction triggered bybending a metal plate. The followingactivity can then be used to introducethe notion of hydration energy and todemonstrate that the reaction bywhich some salts dissolve is anexothermic reaction.

The activity is relatively safe – themost dangerous aspect is the possibil-ity of breaking glass by not handlingit carefully.

Materials per group· About 10 g anhydrous calcium

chloride

· Different sizes of beakers

· Water

· Styrofoam / polystyrene (use rea-sonably large pieces as smallerpieces are a nuisance when theybecome charged and ‘stick’ every-where)

· Two laboratory thermometers

· Soluble coffee powder

· Further items to awaken the stu-dents’ imagination, such as rubberbands, foil, batteries, etc.

The source of the activities:LebensnaherChemie -unter richt

In 2003, four German

chemistry teachers joined

forces to create a web por-

tal to share their best teach-

ing ideas: Lebens naher

Chemie unterrichtw3 (LNCU,

chemistry lessons relevant

to everyday life). Their col-

lection has grown steadily,

and they offer a wide selec-

tion of activities for all age

ranges from primary to

upper-secondary school,

linking to major curricular

topics in chemistry, such as

the periodic table, titration,

and air and water, plus

biology and physics activi-

ties for the youngest stu-

dents.

Their German-language

materials are freely avail-

able as downloadable

PDFs and Word® docu-

ments, with both instruc-

tions for teachers and

worksheets for students. In

addition, the website offers

a range of videos on the

activities and a list of more

(German and English)

websites with teaching

ideas and relevant materi-

als for the science class-

room.BA

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Student worksheet




Potential approachesTwo problems the students often

face are adding too little calcium chlo-ride to the water (the more they use,the more heat will be produced) andforgetting to insulate their beakers.

A common solution to the task is toimprovise a small water bath by plac-ing water and calcium chloride in alarge beaker, and fixing styrofoamaround the beaker with sticky tape.The coffee can then be heated in asmaller beaker in the improvisedwater bath.

The best result within the context ofthe LNCU project (see box) wasachieved by filling a small beakerwith water and placing it in a largerbeaker with a layer of styrofoam in-between for insulation. The studentsthen placed the calcium chloride, towhich they had added very littlewater, in a small film canister.Attaching a string to it and a stone forweight, they let it hang into the water.The temperature of 50 ml of coffeechanged from 20 to 44 °C in less thana minute.

DiscussionDiscuss the apparent contradiction

between the behaviour of cold packsin previous experiments and theexperiment you have just performed –in this case, the solution process is notendothermic. In the cold packs, moreenergy is required to destroy the salt’smolecular lattice (lattice energy) thanis released when water molecules sur-round the ions (hydration energy).

The required energy is drawn fromthe surroundings, so the solutioncools down. In the coffee experiment,in contrast, the hydration energy ishigher than the lattice energy, so theprocess as a whole is exothermic.Hydration and lattice energy are fixedcharacteristics of an individual salt.

Further experimentTo follow this up, the students

could try to achieve the lowest possi-ble temperature using anhydrous cal-cium chloride, sodium chloride andice. They may be surprised to findthat the addition of anhydrous calci-um chloride to ice (rather than water)does not increase the temperature.This is because the hydrogen bonds inthe ice crystals first have to be broken,which requires energy, so that the fullprocess is endothermic.

Web referencesw1 – To order Crosse & Blackwell

heater meals online, see:www.heatermeals.co.uk,www.aapnespis.no orwww.dauerbrot.de

w2 - The ChemZ kits were developedin close collaboration with theLNCU project, and offer a range ofplastic materials normally used inmedicine for use in school labs. Formore information and to ordermaterials, see: www.chemz.de

w3 – The LNCU project is run byGerman chemistry teachers AndyBindl, Andreas Böhm, Gregor vonBorstel and Manfred Eusterholz.For more information (in German)and to access all materials, see:www.lncu.de

w4 – Videos of the heater meals(albeit an older version in which thepacks were in deep plates ratherthan today’s aluminium sachets) areavailable on the Dauerbrot website(www.dauerbrot.de) or via thedirect link:http://tinyurl.com/6ewkvhw

as well as herewww.aapnespis.no/Norsport1_0/show.htm

You can also find a photo demon-stration of how the heater mealsare prepared here:www.mlaltd.co.uk/store

w5 – To download the Englishworksheets of the main heater-meal and the heater-meal science TV show activities, see:www.scienceinschool.org/2011/issue18/lncu#resources

ResourcesFor some microscale chemistry

experiments using disposablematerials, from kindergarten tosecondary-school level (in Englishand German), see:http://www.micrecol.de/

If you find the idea of microscalechemistry experiments appealing,you may also like:

Kalogirou E, Nicas E (2010)Microscale chemistry: experimentsfor schools. Science in School 16: 27-32. www.scienceinschool.org/2010/issue16/microscale

If you enjoyed reading this article,why not take a look at the full listof chemistry articles published inScience in School? See:www.scienceinschool.org/chemistry

Dr Marlene Rau was born inGermany and grew up in Spain.After obtaining a PhD in develop-mental biology at the EuropeanMolecular Biology Laboratory inHeidelberg, Germany, she studiedjournalism and went into sciencecommunication. Since 2008, she hasbeen one of the editors of Science inSchool.

Heating coffee with calcium chloride

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In 2004, Alice Pietsch from theUniversity of Teacher EducationStyriaw1, Austria, was inspired by a

simple but very visual demonstrationat a science museum. A retired scienceteacher was using bellows to pumpair into a pair of sheep’s lungs, rhyth-mically inflating and deflating them.The crowd around him was muchlarger than around many of the morehigh-tech exhibits – which is whatprompted Alice to create an interac-tive science museum.

In 2008, her dream came true. Overfive months, Styrian students of allages developed 50 different activities

for other students. The exhibitionNaturwissenschaft und Technik zumAngreifen (‘Science and technology totouch’) took place in 2009 at the Hausder Wissenschaft (‘House of science’) inGraz, Austria, where the students andtheir teachers helped the visitors witheach activity. It was a huge success.


Biomimetics: clingy as an octopus or slick as a lotus leaf?Astrid Wonisch, Margit Delefant and Marlene Raupresent two activities developed by the Austrianproject ‘Natur wissenschaft und Technik zumAngreifen’ to investigate how technology is inspiredby nature.

Most of the activities from the exhi-bition are suitable for the scienceclassroom; here we present two activi-ties about biomimetics – the applica-tion of principles from nature to engi-neering and technology. Velcro, whichmimicks the hooked seeds of bur-dock, and boat hulls that mimic the

Octopus suction pads

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Science education projectsIm

age courtesy of midlander1231; im

age source: Flickr

Science in School Issue 18 : Spring 2011www.scienceinschool.org 53

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Danger Explanation of danger Likelihood (1 = very Severity (1 = very Prevention or reductionlikely, 5 = very severe, 5 = minor unlikely) inconvenience)

Fretsaw Cut skin 4 3 Train students how to use the saw safely and how to store it when not in use.Hold the pole in a vice if possible while cutting the grooves.

Plants Some may be toxic 5 2 Only bring plants into school that are known to be safeWarn students, especially younger ones, not to eat the plants or put their fingers in their mouths

Some students may be 3 3 Ask students about any known allergiesallergic to some plants or Check any medical records for youngerparts of plants such as pollen students

BiologyChemistryPhysicsAges 5-19

Get stuck in! Or rather, give your students an opportu-nity to get stuck in with the activities described in thearticle.

The stickiness of tree frogs’ feet and of octopus tenta-cles prompts students to explore how this works usingsuction pads. Younger students will enjoy drawingaround their feet and the noises that the suction padsmake as they ‘slurp off’ when pulled. Older studentscan appreciate the physics and explain what is happen-ing using calculations.

The stickiness of honey makes an appearance in thesecond activity, along with ketchup, cinnamon andcurry powder – what student will not enjoy being letloose with these ingredients? Investigating non-sticklotus leaves and nasturtiums leads on to investigatingnovel self-cleaning liquids. This could lead to someinteresting debates, as well as practical work thatranges from simple tasks for young students (rollingwater off leaves) to much more complex work for olderstudents, working with sprays and using scanning elec-tron micrographs to explain phenomena.

The first activity covers physics (pressure) and the sec-ond activity, chemistry (surface interactions), both link-ing to biology with the idea that nature got there first –which could be taken further and investigated by thestudents. If different varieties of leaf are investigated,taxonomy can be introduced as well.

Here are some suggestions for questions you could askyour students after the activities:

1. Draw a diagram to show a suction pad before andafter it is pushed onto a surface. Annotate it to showareas of high, low and equal pressure.

2. The article reminds you that force = area x pressure.Here this is used to calculate the force of a suctionpad. Can you think of some other contexts in whichthis equation could be used?

3. It is very annoying (and noisy) when a shower trayattached by suction pads to a tiled shower wall fallsdown. Explain what might make the suction pads‘fail’ and cause the crash.

4. The article mentions that “dung beetles crawl out ofcowpats”. What might dung beetles be doing insidecowpats and why might they be crawling out? Thismight take some research!

5. A scanning electron microscope is mentioned in thediscussion of the second main activity. What is ascanning electron microscope? How does it differfrom a transmission electron microscope?

6. The bumps on a lotus leaf are up to 20 micrometres(μm) high. Express this height in a) nanometres (nm)and b) millimetres (mm).

7. Explain, in your own words, what is meant by

· Hydrophobic

· Hydrophilic

· Surface tension

· Pollutant

· Inorganic

You could also get your students to carry out a riskassessment for one or both of the activities. Somecountries insist on these. Although it is the teacher’srole to provide a risk assessment, it is thought that ifstudents are involved in creating their own risk assess-ments, they are likely to be much safer as they willhave thought through the dangers themselves. Beloware some suggested responses, although any validresponses or alternatives could be accepted. For someactivities, the likelihood of incidents may vary with theage of the students.

Risk assessment

Sue Howarth, UK



make kitchen machines more stable,and on rubber mats in the shower ortoy arrows. But why do they stick?

If you look at a suction pad closely,you will notice that it is slightlycurved. Could this curvature beimportant for the pad’s adhesivepower? And why do you need to wetsuction pads before using them? Let’sinvestigate.

Materials

· 4 suction pads (make sure you canattach a string to them)

· A small fretsaw

· A 50 cm pole, about 3-4 cm indiameter (the students should beable to wrap their fingers around iteasily)

· Four 50 cm pieces of strong string

· A pair of scissors

· A plastic board (about 1 x 1 m)

· A permanent marker pen

Procedure1. Using the fretsaw, make four equi-

distant grooves in the pole.

2. Tie a piece of string to each of thefour suction pads.

3. Tie the other ends of the string tothe four grooves on the pole. Makesure the four lengths of string areexactly the same length.

4. Put the plastic board on theground, and use the permanentmarker pen to draw four circles forthe suction pads in a straight line.On either side of the line, draw afootprint (see image on page 55).

5. Press the suction pads onto thefour circles.

thick skin of dolphins are commonexamples. The activities below inves-tigate suction pads and superhy-drophobicity, both seen in nature. Theactivities were developed for youngersecondary-school students (aged 10-15), but can easily be adapted for stu-dents of virtually any age and are agood opportunity for integratingphysics, chemistry and biology.Depending on the level of detail yougo into, the activities can each takeanything from five minutes to over anhour.

The full collection of activities from the exhibition is available inprint in German from Birgit Muhr ([email protected]) for €19 pluspostage.

Adhesion on flat surfaces: negative pressure

Household suction pads wereinspired by the soles of tree frogs’ feetand the tentacles of octopuses, whosesuction power was already known tothe ancient Greeks.

We use these pads on flat surfaces –to attach hooks to bathroom tiles or

Image courtesy of Nickodemo; image source: FlickrA tree frog

A fretsaw




also a lower air pressure. The higherpressure of the air outside the pad iswhat keeps the pad stuck to theboard.

You can calculate the force of a suc-tion pad as:

F = AP, where F: force; A: area; p: pressure.

The area will be πr2 where r is theradius of the pad. The pressure insidethe cavity between pad and board isnegligible when compared to atmos-pheric pressure, which is about100 000 Pa. So:

F = πr2 (100 000 Pa)

The time it takes for the pad tocome undone by itself (withoutapplying additional force) willdepend on how porous and flat boththe rim of the pad and the underlyingsurface are, which determines howfast the air leaks back in and equili-brates the pressure.

Water, saliva and other liquids workwell to seal the pad, making it moreairtight and ensuring that air leaksback in less easily. Therefore, youneed even more strength to pull thesuction pads off if you moisten thembefore applying them to a surface.

Self-cleaning effects: hydrophobicity in nature

Nature has some real cleanlinessfanatics: dung beetles crawl out ofcowpats looking spotless, you rarelyfind a dirty butterfly or dragonfly,and some plants are very successful atshedding filth. The Indian lotus, forexample, grows in muddy waters, yetno dirt clings to its leaves; in fact, inBuddhism, the lotus is a symbol ofpurity. You can find this lotus effectcloser to home, too: nasturtium leaves

The setup forthe adhesionactivity.Alternatively, asingle suctionpad and ashorter piece ofwood can beused (see backof the image)

6. What happens to the curvature ofthe suction pads when they arestuck to the plastic board?

7. Stand on the footprints and try topull the suction pads off the plasticby pulling on the pole.

8. Repeat the experiment, wetting thesuction pads before sticking themto the plastic board. What do youobserve?

DiscussionWhen you press the suction pad

onto the plastic board, you reduce thepad’s curvature, thereby reducing thevolume of the space between the padand the board, and causing some ofthe air between the pad and the boardto escape. When you stop applyingpressure, the elastic pad tends toresume its original, curved shape. Thevolume in the cavity between padand board is increased again, butthere is less air in it, and therefore

A scanning electron microscopy imageof a nasturtium leaf showing the com-plex wax structures on the epidermiscells; these structures are responsiblefor the superhydrophobicity

Image courtesy of Professor Edith Stabentheiner,Karl-Franzens-Universität Graz

Image courtesy of tanakaw

ho; image source: Flickr

Image courtesy of PHSt Archiv

A lotus leaf showing off itshydrophobic properties

2μm



and flowers look clean enough to eat,even without washing (rinse themanyway, just in case). How do theymanage without soap?

Humans have replicated this self-cleaning effect for many purposes, forexample, in self-cleaning plastics, rooftiles, windowpanes, ceramics, woodand car varnishes, and façade paint.You can also create dirt-repellentclothes by impregnating them with aspecial spray.

How does it work? Let’s find out.

Materials· Parts of different plants with self-

cleaning properties, such as nastur-tium leaves (Tropaelum majus), lotusleaves (Nelumbo nucifera), cabbageleaves (Brassica oleracea), and tulipleaves (Tulipa spp.)

· Parts of different plants withhydrophilic leaves, such as leavesof the common beech (Fagus sylvat-ica) or the Southern magnolia(Magnolia grandiflora)

· Water, runny honey and / or liquidglue

· A Pasteur pipette and bulb, andsome small spoons

· Ketchup, ground cinnamon andcurry powder

· Newspaper, kitchen roll and textiles

· Impregnation spray (e.g. for water-proofing suede), self-cleaningnano-based façade paint, nano-coating for wood or glass

· Optional: a nano-sealed roof tile

Procedure1. Wet the self-cleaning plants with

water, honey or glue and coverthem with ketchup, cinnamon orcurry powder (to simulate dirt).What do you observe?

2. Repeat the experiment with thehydrophilic leaves. What do youobserve?

3. Now investigate the self-cleaningproperties of artificial materials.Spray textiles, kitchen roll andnewspaper with different types ofnano-sealing treatments (e.g.impregnating spray, paint or nano-coating). Either compare the effect

of the same type of treatment ondifferent materials, or of differenttypes of treatment on the samematerial.

4. Use these and other nano-coatedmaterials (e.g. tiles) to repeat theexperiments, wetting and dirtyingthem. What do you observe?

Safety note: Some students may beallergic to some plants or parts ofplants such as pollen. When usingnano-coating, impregnation spray,etc., carefully read the instructions onthe package. They may require theuse of gloves or a well-ventilatedspace. See also the general safety noteon the Science in School website(www.scienceinschool.org/safety)and on page 65.

DiscussionIf you drop water or honey onto a

lotus leaf, it will roll off very quickly.A close look under a scanning elec-tron microscope reveals why: largenumbers of tiny wax-covered bumpson the surface. These bumps are

The dung beetle remains spot-less even when indulging in itsfavourite pastime

Image courtesy of m

idlander1231; image source: Flickr

Image courtesy of vendys / iStockphoto




about 10-20 μm high and 10-15 μmapart from one another.

How does this structure help thelotus leaf to remain clean? First, thesurface of the lotus leaf is hydropho-bic (water-repellent). The hydropho-bicity of a surface can be quantified asthe contact angle between the surfaceand the drop of water: the higher thecontact angle, the more hydrophobicthe surface (see image to the right).Surfaces with a contact angle <90° arecalled hydrophilic (‘water-loving’);those with a contact angle >90°,hydrophobic. Some plants, which areknown as superhydrophobic, achievecontact angles of up to 160°, with only2-3% of the drop’s surface in contactwith the surface of the leaf. However,the lotus leaf is not only superhy-drophobic but also covered in theaforementioned waxy bumps. Thesereduce the contact surface of thewater droplet still further (imaginethe drop sitting on the points of thebumps), with the result that the dropbarely touches the leaf (only 0.6% surface contact) and runs off easily.

We have seen how the water flowsoff, but how do the leaves get rid ofdirt particles? Plants are exposed to avariety of pollutants, many of whichare inorganic (dust or soot), althoughothers are of biological origin (e.g.fungal spores, conidia, honeydew or

algae). On unwettable leaves such asthose of the lotus, it is not only theadhesion of water to the surface thatis reduced – dirt is also simplywashed away by the water. This is notas obvious as it seems, though: thereare two different types of dirt parti-cles – hydrophilic and hydrophobicones. Hydrophilic particles such assilt are taken up in the water dropletand cannot escape again. A track isvisible on the leaf where the dropshave taken up the particles andwashed them away.

But what about the hydrophobicparticles? You might expect them tostick to the hydrophobic leaf surface,but in fact a drop of water willremove these particles too. How doesthis happen? The particles only touchthe outermost tips of the wax struc-tures, and since this contact surface istiny, so are the adhesive forcesbetween particle and leaf. They are solow that even the small adhesiveforces between the water-repellentparticle and water are stronger. Sounlike the hydrophilic particle, whichis taken into the drop, the hydropho-bic particle sticks to the surface of thedrop. The end effect is the same,though – it is washed off the plant.

Superhydrophobicity is not limitedto lotus plants: other plants have self-cleaning properties thanks to mats of

hair covering their leaves, butterflywings have tiny ratchets that directraindrops away from the insect’sbody no matter whether the wing istilted up or down, and the cuticle ofdung beetles has embossed geometri-cal textures that make it hydrophobic.

What is the advantage of these self-cleaning surfaces? For sedentary

Scanning electron microscopy images (at magnifications of 300x, 2500x and 3000x) showing the wax structures on the sur-face of a rice leaf, similar to those on nasturtium or lotus leaves. The first image shows the waxy bumps amongst the stomata;the second image shows a stoma close up; the third image shows the papillate surface of the leaf and the fine detail of thewax structures

Images courtesy of Sarah Perfect / Syngenta

Droplets of fluid on a surface, demon-strating different levels of hydrophobicity

Image courtesy of MesserWoland; image source: Wikimedia Commons

The contact angle Θ of a water dropleton a surface

On a superhydrophobic surface, a dropwill be almost spherical and have avery low contact angle

Public domain image; image source: Wikimedia Commons

Public domain image; image source: Wikimedia Commons



plants, they are a way of protectingthemselves against micro-organisms,such as fungi, bacteria or algae. Mostplants fight these enemies chemicallythrough a large range of secondarymetabolites, but preventing themfrom settling in the first place ispotentially even more effective. In

addition, if leaves are covered in dirt,this reduces the surface available forphotosynthesis. The self-cleaningwings of butterflies have the advan-tage of not retaining water andbecoming heavy, which would pre-vent the insects from flying.

Humans have developed manytypes of technology that emulatethese hydrophobic effects.Impregnation sprays, for example,cover the material with a wax-likecoating that makes the materialshydrophobic. Some façade paints goeven further, forming tiny bumpswhen they dry. These bumps are aswater-repellent as the lotus’s waxstructures with the result that thepainted surface becomes superhy-drophobic.

AcknowledgementsThe two activities in this article

were developed in the context of aworkshop led by Astrid Wonisch forstudents of the Karl-Franzens-Universität Graz who were training tobecome biology teachers, and includ-ed in the 2008 exhibitionNaturwissenschaft und Technik zumAngreifen.

Biology students Steffen Böhm andKarin Edlinger worked together withstudents from the combined 7th and 8th

grade (aged 17-19) biomimetics classat the secondary school BG / BRGPetersgasse, Graz, a secondary schoolwith a science and maths focus, andthe school’s biology teachers, RenateRovan and Ruth Unger, on ‘Adhesion

Image courtesy of Sebastian; im

age source: Flickr

Close-up of a butterfly wing

Image courtesy of W

illiam Thielicke; im

age source: Wikim

edia Com

mons

Illustration of thelotus effect




on flat surfaces: negative pressure’.

Biology students AnnaFreudenschuss and Ingo Fuchsworked together with students from a4th grade (aged 14-15) class at the sec-ondary school BG / BRG Fürstenfeld,Fürstenfeld, on ‘Self-cleaning effects:hydrophobicity in nature’.

Web referencew1 – To learn more about the

University of Teacher EducationStyria, see: www.phst.at

ResourcesThe German TV channel SWR has

produced a series of short videos onsuction pads in nature and technol-ogy, with accompanying teachingmaterials (in German). See theireducation website Planet Schule(www.planet-schule.de) or use thedirect link:http://tinyurl.com/6gey6tg

The following website offers a wealthof information on the lotus effect inEnglish and German, including asmall collection of videos:www.lotus-effekt.com

For primary-school teaching activitieson hydrophobicity and the surfacetension of water, see:

Kaiser A, Rau M (2010) LeSa21:

primary-school science activities.Science in School 16: 45-49.www.scienceinschool.org/2010/issue16/lesa

For a more in-depth overview of bio-inspired design, comparing theachievements of nature and technol-ogy, see:

Vincent J (2007) Is traditional engi-neering the right system with whichto manipulate our world? Science inSchool 4: 56-60. www.scienc einschool.org/2007/issue4 /biomimetics

For more information on biomimicry,see the Ask Nature website:www.asknature.org

For further teaching activities onsuperhydrophobicity and nano-waterproofing for different ageranges, see:

The EGFI website:http://teachers.egfi-k12.org/nano-waterproofing

The Nanoyou website(http://nanoyou.eu) or use thedirect link:http://tinyurl.com/6d88zmd

The NanoEd resource portal(www.nanoed.org) or use the directlink to the PDF:http://tinyurl.com/6dwxo2b

For more nanotechnology-relatedresources for the classroom, see:

Harrison T (2006) Review of Nano:the Next Dimension andNanotechnology. Science in School 1:86. www.scienceinschool.org/2006/issue1/nano

Hayes E (2010) School experimentsat the nanoscale. Science in School 17:34-40. www.scienceinschool.org/2010/issue17/nano

Mallmann M (2008)Nanotechnology in school. Sciencein School 10: 70-75.www.scienceinschool.org/2008/issue10/nanotechnology

If you enjoyed reading this article,why not take a look at our full collection of teaching activities

published in Science in School? See:www.scienceinschool.org/teaching

Dr Astrid Wonisch teaches plantphysiology at Karl-Franzens-Universität Graz, Austria. She is headof the university’s didactics centre forbiology and environmental scienceand works with students who aretraining to become biology teachers.

Margit Delefant is the deputy direc-tor of the regional didactics centre forbiology and environmental science inStyria, Austria. She splits her timebetween teaching at the secondaryschool BG / BRG Fürstenfeld and atthe Karl-Franzens-Universität Graz,where she teaches didactics to futurebiology teachers.



Scanning electron micro-graph of the minute scalesthat form the surface of aPeacock butterfly wing (magnification 50x)

A droplet of water on thesurface of a wheat leaf

Images courtesy of C

lifford Hart / Syngenta

Image courtesyof SecretD

isc;im

agesource;

Wikim

ediaC

omm

ons



Image courtesy of Henrik5000 / iStockphoto

Binnig and his colleagues continuedto search for better solutions, and in1986, presented the atomic forcemicroscope (AFM), which can be usedto image both conducting and non-conducting materials.

The instrument works not unlike arecord player, in which a sharp needlescans a vinyl record to reproducesound (see image on page 62). TheAFM ‘feels’ the atoms, rather than‘seeing’ them: the structure of a sur-face is scanned with a very sharpcone (typically of silicon or siliconnitride) at the end of a flexible can-tilever that can follow even the small-

est details of the surface. When thetip, consisting of a single atom, comesclose to the sample surface, it isdeflected through forces between thetwo: these can be mechanical contactforces, van der Waals forces, capillaryforces, chemical bonding, electrostaticforces, magnetic forces, Casimirforces, solvation forces or others,depending on the nature of the speci-men.

Because this variety of forces can bemeasured with the AFM, it is veryversatile and has led to an explosionin the number of scientists using theinstrument – mostly but not only formaterial sciences and biology. In eachcase, the force causing the deflectionis tiny and proportional to the tip’sdistance from the surface.

How can these tiny deflections bemeasured? The inventors used aclever trick: a laser spot is shone ontothe top of the cantilever, from whereit is reflected onto a position-sensitivelight detector. The change in the laserspot’s position on the detector (seediagram on page 61, ΔH) due to adeflection of the cantilever (see dia-gram on page 61, Δh) is proportional

Single moleculesunder the microscope

The idea of looking at singlemolecules or atoms has fasci-nated scientists for over a hun-

dred years. This ambitious goal wasfirst achieved in 1981 with the inven-tion of scanning tunnellingmicroscopy, for which Gerd Binnigand Heinrich Rohrer at the IBMResearch Laboratory in Rüschlikon,Switzerland, were awarded the NobelPrize in Physics some time later, in1986w1. This microscope has a severelimitation though: it works only onelectrically conducting objects, somany interesting materials includingbiomolecules could not be studied.

Image courtesy of lovestruck; im

age source: Flickr

Boats sufferingfrom biofouling


Position-sensitive detector detector

Laser

Detector &feedbackelectronics

Sample surfacerfaceΔh

ΔH

Science topics


PhysicsBiologyMedicinePhysiologyAges 14-19

This article would be suitable for a wide range of sci-ence lessons – not only in physics but also when con-sidering animal physiology or biomedical sciences,for example.

Students can research atomic force microscopy andits uses further, as there is plenty of material on theInternet about the advantages and disadvantages ofvarious microscopy techniques. They could also lookup the group of scientists who invented the atomicforce microscope (having won a Nobel Prize for aprevious invention) and find out more about themand their work.

Potential comprehension questions include:

1. What was the limitation of scanning tunnellingmicroscopy?

2. What microscope was developed to overcome theproblems of scanning tunnelling microscopy?

3. Explain how AFM is like a vinyl record (please notethat some students may not be familiar with vinylrecords).

4. Explain the term biofouling.

5. Why is biofouling a problem?

6. Give examples of potential uses of AFM.

7. What would you like to investigate if you had anAFM?

The article could be used with groups of older stu-dents or those most able to think creatively, perhapsfor an extended writing task in conjunction with thefilm Honey I Shrunk the Kids (about a scientist work-ing on a top-secret machine that miniaturises objectsand – accidentally – people), to get the students tothink about looking at single molecules. What wouldthey like to use AFM for? Would they use their imagesas art or for scientific research? Would they want touse their knowledge to cure diseases or to see howbeautiful science can be at this level?

Jennie Hargreaves, UKRE

VIE

W

Would it not it be fascinating to observe and manipulate individ-ual molecules? Patrick Theer and Marlene Rau from the EuropeanMolecular Biology Laboratory explain how, with an atomic forcemicroscope, you can do just this. You could even build your own.

Science in School Issue 18 : Spring 2011 61

to the distance between the detectorand cantilever. With large enough dis-tances between them, even tinydeflections can be measured, makingit possible to study the structure ofsurfaces atom by atom.

The applications of the AFM aremyriad. Let us take a brief tour of justa few of them.

Originally, AFM was developed toobserve and analyse surface struc-

How the deflections of the AFM tip are magnifiedand measured

Image courtesy of Patrick Theer


www.scienceinschool.org62

tures in minute detail – not only isthis interesting for research purposes,but it can have direct economic bene-fits: biofouling is the undesirableaccumulation of micro-organisms,plants, algae and / or animals (suchas barnacles, Cirripedia) on wet struc-tures. On ship’s hulls, high levels offouling can increase water resistanceand thus substantially increase fuelconsumption, but it is also an issue inmembrane bioreactors, cooling watercycles of power stations and certainoil pipelines. Scientists use AFM tomeasure the degree of biofouling andthus compare the anti-biofoulingactivity of different substances, toidentify the ideal material (Finlay etal., 2010).

Similarly, AFM has its uses in agri-culture: pineapple plants often sufferfrom a fungal disease called fusario-sis. Scientists compared the surfacestructure of cells from pineapple culti-vars that are resistant to this diseasewith those of susceptible cultivars,and found that they have differentmechanical properties. This can nowbe used to select and improve resist-ant cultivars that have the requiredmechanical properties (de FariasViégas Aquije et al., 2010).

Is surface structure relevant tohuman health, too? The answer is yes:AFM studies are often used in den-tistry, for example to compare theeffectiveness of different methods toremove plaque and stains; to measurethe surface roughness of braces andsee how this influences the effective-ness with which the teeth are pulledinto shape; or to quantify the erosionof tooth enamel caused by acid in softdrinks and test the efficacy of varioustoothpastes in repairing this damage(Kimyai et al., 2011; Lee et al., 2010;Poggio et al., 2010).

Other medical applications includethe development of new biomaterialsin regenerative medicine: their surfaceproperties such as wettability, rough-ness, surface energy, surface charge,chemical functionalities and composi-

Another major field of applicationfor AFM in medical biology is themisfolding and aggregation of pro-teins such as α-synuclein, insulin, pri-ons, glucagon and β-amyloid. Thesephenomena have long been implicat-ed in degenerative diseases such astype II diabetes, Parkinson’s, spongi-form encephalopathy (‘mad cow dis-ease’), Huntington’s and Alzheimer’s.Here AFM has already providedimportant information on thenanoscale structure of the aggregates,and it is hoped that scientists will beable to use AFM to identify why theprotein misfolds in the first place, andhow it encourages surrounding pro-teins to adopt the same misfoldedstructure (Lyubchenko et al., 2010; foran explanation of prion misfolding,see Tatalovic, 2010).

Further biological interactions thathave been studied with AFM includehow human trophoblasts (cells form-ing the outer layer of a blastocystwhich provide nutrients to theembryo and develop into a large partof the placenta) interact with epithe-lial cells of the uterus – the basis ofsuccessful embryo implantation (Thieet al., 1998).

It was only a small step from usingAFM for observations to using it tomanipulate atoms, molecules or other

The needle is poisedover a vinyl record,ready to begin scan-ning its surface to produce sound

Image courtesy of arbobo; image source: Flickr

Image courtesy of Frantysek / iStockphoto

tion can determine the behaviour ofthe cells they will come into contactwith. Thus AFM can be used, forexample, to help design biomaterialsthat are tolerated by the body and canbe used for medical implants such asartificial hips (Al-Ahmad et al., 2010;Kolind et al., 2010; Padial-Molina etal., 2011).

Image courtesy of arbobo; image source: Flickr



Science topics


nanoscale structures. For example,using the tip as nano-tweezers, pre-cise regions of the cell’s plasma mem-brane can be examined; individualprotein loops can be removed toreveal the protein structure inside themolecule; and single molecules can bestretched into novel conformations todetermine their elasticity. The next bigstep will be using AFM fornanosurgery: introducing or extract-ing individual molecules from thecytoplasm of individual cells, to studycellular homeostasis or for subcellulardrug delivery (Lamontagne et al.,2008; Müller et al., 2006).

Modified AFM tips can also be usedas drills or pens: nano-millingremoves material in the form of longcurled chips (Gozen & Ozdoganlar,2010), whereas dip-pen nanolithogra-phy is the controlled delivery of

molecular or liquid ‘ink’. In chemistryand the life sciences, such technologyis used to produce nanoscale sensorsor, by the deposition of metallic, semi-conductor and metal oxide nanostruc-tures, functional nanocircuits or nan-odevices (Basnar & Willner, 2009).This, combined with using the AFMtip to physically push nanometre-sized particles to a desired position,should pave the way for the miniatur-isation of electronic circuitry andother structures.

Despite its vast number of applica-tions – these are just a small sample –the possibilities of AFM are not yetexhausted. Future trends involve opti-mised tips and combinations withother techniques, for example tosimultaneously determine surfacestructure and fluorescence or electri-cal properties (Müller et al., 2006).Speed is another issue: recently, anAFM has been developed with whichbiological processes such as chromo-some replication and segregation,phagocytosis and protein synthesiscan be imaged in real time, up to 1000times faster than was previously pos-sible (Ando et al., 2008).

Are you now itching to come upwith your own applications for AFM?Then you might want to try and fol-low Philippe Jeanjacquot’s instruc-

tionsw2 for building your own instru-ment at school. It is a time-consumingproject, but he and his students man-aged to create a feasibly low-costmicroscope. There is one importantcatch though: you will need a vibra-tion-free environment to set it up,such as a quiet cellar. If you can findthat, your enthusiasm and ingenuityare the only limitations.

ReferencesAl-Ahmad A et al. (2010) Biofilm for-

mation and composition on differ-ent implant materials in vivo.Journal of biomedical materialsresearch. Part B, Applied Biomaterials95(1): 101-109. doi:10.1002/jbm.b.31688

Ando T et al. (2008) High-speed AFMand nano-visualization of biomolec-ular processes. Pflügers Archiv:European journal of physiology 456(1):211-225. doi: 456(1):211-25

Basnar B, Willner I (2009) Dip-pen-nanolithographic patterning ofmetallic, semiconductor, and metaloxide nanostructures on surfaces.Small 5(1): 28-44. doi:10.1002/smll.200800583

de Farias Viégas Aquije GM et al.(2010) Cell wall alterations in theleaves of fusariosis-resistant and

The European Synchrotron RadiationFacility has developed an atomicforce microscope especially for useon X-ray beamlines. One possibleuse is positioning nano-sized objectsaccurately in the X-ray beam. This isnot a trivial task if both the objectunder study and the X-ray beammeasure 100 nm or less across

Image courtesy of ESRF / Small Infinity

Image courtesy of webking / iStockphoto

AFM has a full set of tooth-relatedapplications



susceptible pineapple cultivars.Plant Cell Reports 29(10): 1109-1117.doi: 10.1007/s00299-010-0894-9

Finlay JA et al. (2010) Barnacle settle-ment and the adhesion of proteinand diatom microfouling to xerogelfilms with varying surface energyand water wettability. Biofouling:The Journal of Bioadhesion and BiofilmResearch 26(6): 657-666. doi:10.1080/08927014.2010.506242

Gozen BA, Ozdoganlar OB (2010) Arotating-tip-based mechanical nano-manufacturing process:nanomilling. Nanoscale ResearchLetters 5(9): 1403-1407. doi:10.1007/s11671-010-9653-7. The fulltext article is freely available online.

Kimyai S et al. (2011) Effect of threeprophylaxis methods on surfaceroughness of giomer. Medicina Oral,Patología Oral y Cirugía Bucal 16(1):e110-e114. doi: 10.4317/medo-ral.16.e110. The full text article isfreely available online.

Kolind K et al. (2010) A combinatorialscreening of human fibroblastresponses on micro-structured sur-faces. Biomaterials 31(35): 9182-9191.doi:10.1016/j.biomaterials.2010.08.048

Lamontagne CA, Cuerrier CM,Grandbois M (2008) AFM as a toolto probe and manipulate cellularprocesses. Pflügers Archiv: Europeanjournal of physiology 456(1): 61-70.doi: 10.1007/s00424-007-0414-0

Lee GJ et al. (2010) A quantitativeAFM analysis of nano-scale surfaceroughness in various orthodonticbrackets. Micron 41(7): 775-782. doi:10.1016/j.micron.2010.05.013

Lyubchenko YL et al. (2010)Nanoimaging for protein misfold-ing diseases. Wiley InterdisciplinaryReviews (WIREs). Nanomedicine andNanobiotechnology 2(5): 526-543.doi: 10.1002/wnan.102

Müller DJ et al. (2006) Single-mole-cule studies of membrane proteins.Current Opinion in Structural Biology16(4): 489-495. doi:10.1016/j.sbi.2006.06.001

Padial-Molina M et al. (2011) Role ofwettability and nanoroughness oninteractions between osteoblast andmodified silicon surfaces. Acta bio-materialia 7(2): 771-778. doi:10.1016/j.actbio.2010.08.024

Poggio C et al. (2010) Impact of twotoothpastes on repairing enamelerosion produced by a soft drink:an AFM in vitro study. Journal ofDentistry 38(11): 868-874. doi:10.1016/j.jdent.2010.07.010

Tatalovic M (2010) Deadly proteins:prions. Science in School 15: 50-54.www.scienceinschool.org/2010/issue15/prions

Thie M et al. (1998) Interactionsbetween trophoblast and uterineepithelium: monitoring of adhesiveforces. Human Reproduction 13(11):3211-3219. doi: 10.1093/hum-rep/13.11.3211. The full text articleis freely available online.

Web referencesw1 – To learn more about the discov-

ery of the scanning tunnellingmicroscope, which won GerdBinnig and Heinrich Rohrer theNobel Prize in Physics in 1986, see:http://nobelprize.org/nobel_prizes/physics/laureates/1986

w2 – To download the instructions forbuilding your own AFM at school,see: www.scienceinschool.org/2011/issue18/afm#resources

ResourcesSwiss scientists have developed the

first AFM for planetary science,which forms part of NASA’sPhoenix mission to Mars. For avideo introduction, see the Azonanowebsite (www.azonano.com) or follow the direct link:http://tinyurl.com/6yguvb9

‘Universe today’ reports on theinstrument’s success in the mission.See their website(www.universetoday.com) or followthe direct links: snow on Mars(http://tinyurl.com/6kp3rym)

and Martian dust grains(http://tinyurl.com/64z6xrb)

If you enjoyed reading this article,why not browse the full collectionof science topics published inScience in School? See:www.scienceinschool.org/sciencetopics

Dr Patrick Theer is a physicist whohas spent most of his career develop-ing microscopy techniques. Afterstudying medical physics in Berlin,Germany, in Toronto, Canada, and inGuildford, UK, he delved into thefield of non-linear optics for a PhD atthe University of Heidelberg,Germany, studying the imaging depthlimit in two-photon microscopy – anoptical sectioning method that canprovide information from very deepwithin scattering tissues. For his post-doctoral work, he moved on to theUniversity of Washington in Seattle,USA, studying voltage-sensitive dyesusing second harmonic generationmicroscopy. Currently, he works as a senior research assistant at theEuropean Molecular BiologyLaboratory in Heidelberg, developinga light-sheet-based fluorescencemicroscope for the study of embryon-ic development.

Dr Marlene Rau was born inGermany and grew up in Spain. Afterobtaining a PhD in developmentalbiology at the European MolecularBiology Laboratory, she studied jour-nalism and went into science commu-nication. Since 2008, she has been oneof the editors of Science in School.

To learn how to use thiscode, see page 65.


Safety noteFor all of the activities published in Science inSchool, we have tried to check that all recog-nised hazards have been identified and thatsuitable precautions are suggested. Usersshould be aware, however, that errors andomissions can be made, and safety standardsvary across Europe and even within individualcountries.Therefore, before undertaking any activity,users should always carry out their own riskassessment. In particular, any local rulesissued by employers or education authoritiesMUST be obeyed, whatever is suggested in theScience in School articles.Unless the context dictates otherwise, it isassumed that:

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Publisher: EIROforum,www.eiroforum.org

Editor-in-chief: Dr Eleanor Hayes, European Molecular BiologyLaboratory, Germany

Editor: Dr Marlene Rau, European Molecular BiologyLaboratory, Germany

Editorial board:

Dr Giovanna Cicognani, InstitutLaue Langevin, France

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Dr Dean Madden, National Centrefor Biotechnology Education,University of Reading, UK

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Lena Raditsch, EuropeanMolecular Biology Laboratory,Germany

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Copy editor: Dr Caroline Hadley

Composition: Nicola Graf, Email: [email protected]

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untary work at a secondary boardingschool, Apred Ndera, about 5 milesfrom the capital Kigali, it was theeducation system that caught hisattention.

“Students there are usually well-motivated and have a strong desire todo well, knowing that the way tomove on is to get a good education,”says David, who works at CliftonCollegew1, a boarding school in Bristol,UK. “Unfortunately, though, discus-sion forms no part of the way they aretaught. Often they just copy the work

Teacher solidarity: a UK-Rwandan physics projectThanks to the determination of UK physics teacher DavidRichardson, increasing numbers of students in Rwandanschools are experiencing the delight of practical work. Vienna Leigh reports.

Mention Rwanda and, evennow, people are most likelyto think of its troubles; the

Rwandan genocide, 1994’s masskilling of 800 000 people, is not some-thing that can – or should – be easilyforgotten. Today, though, this east-central African country is one of thecontinent’s success stories, with anefficient government, notable eco-nomic growth and even a flourishingtourism industry. But when, in 2004,physics teacher David Richardson vis-ited a colleague who was doing vol-

Clifton Collegein Bristol, UK

Image courtesy of G

reen Lane; image source: W

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ons

Image courtesy of Zach Harden; image source: Wikimedia Commons


Teacher profile


physics, mostly due to a lack of appa-ratus,” he says. “Any equipment theyhave is often incomplete or broken, orthey simply don’t know how to use it.They hadn’t even seen simple electriccircuits, and none could connect up abattery pack to bulbs when I broughtthese into the lesson.”

David was inspired to put togethera one-hour show covering theschool’s physics syllabus. “I spenttwo weeks collecting together appara-tus to demonstrate standing waves,oscillations in a pipe, Doppler andother wave effects,” he explains. The

results were more than he could havehoped for. “Thanks only to word-of-mouth publicity around the school,the hall was packed with 300 stu-dents! It was great fun. When I havebeen back to visit, students tell methat they still remember the physicsthey witnessed that day.”

This persuaded David to try to dosomething to improve the practicalwork in Rwandan secondary schools.He looked at how practical workcould be fitted into the school syl-labus. “I made a list and returnedhome with a mission to find a way toget the necessary equipment to stu-dents in Rwanda,” he explains.

During the following year, heapproached the international depart-ment of the UK-based Institute ofPhysicsw2 (IOP) to see if they wouldfund his idea. “My aim was to takeenough apparatus to allow fiveschools to carry out demonstrations inwaves, dynamics, optics, electronicsand modern physics,” he says. “Iplanned to take four colleagues withme in the summer holidays, to workwith ten local teachers, training themto use the apparatus and giving themthe confidence to use it with theirown classes.”

The IOP agreed to the funding, andin August 2005, David, accompaniedby IOP network coordinator DavidGrace, and a team from GordanoSchool, Portishead – head of physicsPaul Crossthwaite, teacher PaulWelch and 18-year-old Adam Aziz,selected from among many studentapplicants – travelled back to Kigali.“Training the teachers was an amaz-ing experience,” says David. “I wasimpressed with the hard work that

they put in. There was no shyness;everyone wanted to learn, and theywere all friendly and pleased to bethere. They were very excited toknow what was in the first box!”

Even at mealtimes, the conversationoften turned to physics. “It was inter-esting to hear about the politics of theeducation system, and how teachersworked within this at their schools,”says David.

David began by showing them cir-cuit apparatus. “They performed theexperiments with care and precision,making careful notes, and weredelighted that they would be able totake the apparatus away with them,”he recalls.

The teachers repeatedly came upwith further ideas about equipmentthat they would like to be able toshow their students. “You reallyappreciate how privileged we are inthe UK when you see a teacher look-ing forward to the chance to usebulbs, batteries and ammeters withtheir classes for the first time,” saysDavid.

The project did not stop there.When David repeated the exercise inthe summer of 2006, the IOP fundingallowed the number of schools receiv-ing the apparatus to be increasedfrom five to ten. In addition,

from the board and try to understandit later. Teachers aren’t valued in soci-ety and aren’t well paid, with manyhaving more than one job to makeends meet. They can also simplydecide to leave one school to go andwork elsewhere with no warning,meaning students are suddenly leftwith no teacher.”

During his visit, David taught thesenior 5 maths and physics class – 17-year olds – in their free periods.“Practical work isn’t common inRwandan schools, particularly in

The flag of Rwandans

Students at Ada Senior HighSchool and Asi DaaheyInternational Junior HighSchool in Ada, Ghana

Image courtesy of Ernest Nanor

Rwanda is located ineast-central Africa

Image courtesy of JonGorr / iStockphoto



Rwandan teachers who had beentrained in 2005 carried out the train-ing instead of their British counter-parts. “I felt that this was important,so that the Rwandan teachers felt theywere sharing what they had learnedwith other colleagues from across thecountry,” he says. “It was encourag-ing to hear how they had been usingthe apparatus they had been given,and about the impact that this hadhad on their students.”

In addition, the IOP had also agreedto fund a workshop in which theapparatus required could be assem-bled locally. Two technicians – formerstudents at Apred Ndera – weretrained to make the equipment. “Over12 months, they produced 65 com-plete sets of apparatus ready to bedistributed to schools in Rwanda,”says David. “They displayed whatthey produced at an education exhibi-tion for Rwanda and Uganda, andmany people commented on the qual-ity, hardly believing that it was pro-duced locally.” It was at this pointthat the science journal Naturew3 heardabout the project. They are paying thesalaries of the two technicians, initial-ly for three years, and provide themoney to buy enough components tobuild 100 sets of apparatus each year.

The final stage was to introduce alocal project manager, so the projectcould be run from Rwanda. Sincethen, David has met with representa-tives from the Rwandan governmentto discuss the importance of practicaldemonstrations in secondary-school

education. The IOP and Nature areworking with the Kigali Institute ofEducationw4 to ensure that the projectis sustainable. A similar IOP project isbeing rolled out in Ethiopia, and thereare plans to extend the initiative toother African countries includingGhana, Tanzania, Uganda andMalawiw5.

“I hope and believe that this projectprovides a good model of how tostart to introduce practical work intosecondary science education,” saysDavid. “I’m looking forward to seeinghow the government responds to thischallenge and trust that, ultimately, itwill be the students who see the bene-fit: improved physics teaching.”

Web referencesw1 – Find out more about Clifton

College, Bristol, on their website:www.cliftoncollegeuk.com

w2 – The UK-based Institute ofPhysics is a scientific charity devot-ed to increasing the practice, under-standing and application of physics.See: www.iop.org

w3 – To find out more about the sci-ence journal Nature and associatedactivities, see: www.nature.com

w4 – Learn more about the KigaliInstitue of Education, a young pub-lic institution of higher learning inRwanda, here: www.kie.ac.rw

w5 –To help support physics educa-tion in some of the poorest coun-tries in the world, you can donateonline to the IOP’s Physics for

Development programme. See:www.iop.org/about/international/development/africa

ResourcesIf you enjoyed reading this article,

why not take a look at our otherteacher profiles published in Sciencein School? See:www.scienceinschool.org/teachers

Vienna Leigh studied linguistics atthe University of York, UK, and has amaster’s degree in contemporary lit-erature. As well as spending severalyears as a journalist in London, shehas worked in travel and referencepublishing as a writer, editor anddesigner. She then widened her scien-tific horizons at the EuropeanMolecular Biology Laboratory inHeidelberg, Germany, before movingto the Institute for Bioengineering ofCatalonia, Spain, as the head of com-munications.

Image courtesy of R

ollingEarth / iStockphoto

Images courtesy of Ernest Nanor

Students at Ada Senior High School and Asi Daahey International Junior High School in Ada, Ghana

To learn how to use this code, see:www.scienceinschool.org/help#QR


Scientist profile


To sea with a blind scientist

RE

VIE

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BiologyGeneral scienceAges 12-15

This article could be used to introduce any scientificsubject, whether biology, geology, general sciences orsomething else. It could be used to discuss whatworking in science actually involves. Being a (blind orsighted) scientist involves so much exciting collabora-tive work: fieldwork, conferences in many differentcountries, writing articles, reviewing the work of otherscientists, supervising PhD students and, of course,teaching. This article is perfect for a classroom discus-sion to ‘unmake’ the myth that working in sciencemeans being closed up all day alone in a laboratory.

This discussion could also be used to emphasise thatscientists are normal people (whether blind or not)who build their careers on hard work and continuousstudy (see also the review of Leigh, 2010).

Questions relating to the article that could be asked inthe classroom include:

1. The author refers to biology as “that most visual ofall the sciences”. Do you agree with this statement?

2. Do you agree that science is that most powerful ofall ways of knowing?

3. After reading the article, describe in your ownwords what ‘being a scientist’ means.

Alternatively, the question could be asked to thestudents before reading the article. After the stu-dents have read the article, compare and discuss if/ how their views of being a scientist have changed.

4. Geerat Vermeij is a successful (blind) biologist.After reading the article, what more would you liketo know about him and his work? Write three orfour questions and briefly justify each question.

Betina da Silva Lopes, Portugal

Scientific research is not a career that most people believe to besuitable for the blind, but such beliefs are changing. BiologistGeerat Vermeij explains that, whether you are blind or not, science is competitive, tedious and hard – and he loves it.

Braille

Image courtesy of domi-san; image source: Flickr

Image courtesy of YinYang / iStockphoto



How, a sceptic might ask,could a blind person everhope to be a scientist? After

all, science is difficult even for manysighted people. How would I carryout experiments or read the huge sci-entific literature? Perhaps a blind per-son could be a theoretical physicist,but surely not a biologist. Why wouldthe blind willingly choose biology,that most visual of all the sciences?

The answer is very simple: biologyfascinates me. Someone is actuallypaying me to study shells – some ofthe most beautiful works of architec-ture in all of nature. What is more, Iget to travel to exotic places, read thescientific literature in all its fantasticdiversity, see my own papers andbooks published, and teach othersabout science, that most powerful ofall ways of knowing. What morecould one ask of a profession?

Like many of my colleagues, I cameto science early in life. Even as a smallboy growing up in the Netherlands, Ipicked up shells, pine cones and pret-ty stones. My parents, both of whomare avid natural historians, encour-aged me; the fact that I was totallyblind made no difference at all. At theage of ten, shortly after moving to theUSA, I became seriously interested inshells and started my own collection.My parents and brother were enthusi-astic; they read aloud, transcribed ordictated every book on natural histo-ry they could find.

The reactions of my teachers atschool ranged from polite acceptanceto genuine enthusiasm when I toldthem of my intentions to become abiologist. If they thought blindnessand biology were incompatible, theykept it to themselves.

I moved on to study biology andgeology at Princeton University,where I received strong support fromnearly all of my professors, and thenapplied to do doctoral work at YaleUniversity. The interviewer wasapprehensive; he took me down tothe university’s shell collection and

asked me if I knew two of the speci-mens. Fortunately, the shells werefamiliar to me and his misgivingsevaporated. After my PhD at Yale, Imoved to the University of Marylandat College Park, becoming a professorthere in 1980. In 1988, I moved to theUniversity of California, Davis, as aprofessor of geology. Along the way, Imarried a fellow biologist and we hada daughter, Hermine, who is now 29.

What do I actually do in my job thatseemed so improbable to the sceptics?Again the answer is simple. I do whatmy sighted colleagues do: research,teaching and administration.

My research centres on how ani-mals and plants have evolved to copewith their biological enemies – preda-tors, competitors and parasites – overthe course of the last six hundred mil-lion years of Earth’s history. When Iwas still a PhD student, I noticed thatmany of the shells I found were bro-ken, despite their considerable thick-ness and strength. It soon becameclear that shell-breaking predators,

especially crabs and fishes, wereresponsible for this damage. I beganto suspect that many of the elegantfeatures of tropical shells – their knob-by and spiny surfaces, their tight coil-ing, and the narrow shell openingoften partially occluded by knob-likethickenings – could be adaptations toprotect the snails inside from theirpredators.

How do I do my research? I com-bine field, laboratory, museum andlibrary work, visiting coral reefs,mangrove swamps, deserts, rainforests, research vessels, marine bio-logical stations, secret military instal-lations, great libraries and big-citymuseums all over the world. I collectspecimens in the field, work with liv-ing animals in laboratory aquaria,measure shells in museums and in myown very large research collection,and read voraciously.

Wherever I go I am in the companyof a sighted assistant or colleague.There is nothing unusual about this;every scientist I know has assistants.

As a PhD student, Geerat Vermeij wonderedwhether some molluscs had evolved elabo-rate shells such as this to ward off predators

Image courtesy of busypix / iStockphoto

Image courtesy of m

almesjo; im

age source: Flickr


Scientist profile


At the library, as my reader reads tome, I transcribe extensive notes on thePerkins Brailler. My Braille scientificlibrary now comprises more than 17 000 publications compiled in morethan 300 thick Braille volumes.

Like many of my colleagues, Ispend a great deal of time writing.First, I prepare drafts on the PerkinsBrailler, then type the manuscript onan ink typewriter. An assistant proof-reads and corrects the manuscript,which is then submitted to a journal.So far, I have published 205 peer-reviewed papers and books in thisway.

Teaching has always been inextrica-bly intertwined with research for me.Over the years I have taught a greatvariety of courses – animal diversity,evolutionary biology, ecology, marineecology, malacology, the mathematicsand physics of organic form, and aseminar on extinction. In the largeintroductory courses, teaching assis-tants take charge of the laboratorysections and help in grading papers.Again, there is nothing unusual inthis: science professors at most uni-versities depend heavily on teachingassistants (as a PhD student, I myselfwas lucky enough to receive fullfunding, which meant I did not needto be a teaching assistant).

Like other research-oriented profes-sors, I also train graduate students.Thus far, 15 students have receivedtheir PhDs under my direction.

Of course, science isn’t all fun andgames: it is competitive and hardwork, full of tedious calculations, dis-appointment when a cherished paperis rejected, or quibbling about gradeswith a frustratingly inept student.Nobody in science is exempt fromthis, but in the end the work isimmensely rewarding.

In short, there is nothing about myjob that makes it unsuitable for ablind person. Of course, there areinherent risks in the fieldwork; I havebeen stung by rays, struck down bystomach cramps and detained by

police who mistook me for an opera-tive trying to overthrow the govern-ment of their African country. Allfield scientists have similar experi-ences. The blind, no more than thesighted, must act sensibly and withappropriate caution. Along with inde-pendence comes the responsibility ofassuming risks.

What would I say to a blind personwho is contemplating a career in sci-ence? Very simple. I would tell thatperson exactly what I would tell asighted one: love your subject, be pre-pared to work hard, don’t be discour-

aged, be willing to take risks, get asmuch basic science and mathematicseducation as you can take, and per-haps above all, display a reasonedself-confidence without carrying achip on your shoulder. You will needstamina, good grades, the support ofinfluential scientists, and a willing-ness and ability to discover new factsand new ideas. It is not enough to dowell in courses; you must make newobservations, design and testhypotheses, and interpret and presentthe results in such a way that thework is both believable and interest-

Image courtesy of cobalt123; image source: Flickr



ing to others. Science is not for every-one, but I can think of no field that ismore satisfying.

AcknowledgementThis article is reproduced with the

permission of the NFB; a longer ver-sion of the article was published onthe NFB website:http://nfb.org/legacy/books/kernel1/kern0610.htm

ReferenceLeigh V (2010) Sowing the seeds of

science: Helke Hillebrand. Science inSchool 15.www.scienceinschool.org/2010/issue15/helke

ResourcesNot all blind children attend a main-

stream school like Geerat Vermeijdid; there are also schools especiallyfor blind and partially sighted stu-dents. To learn more about one suchschool, and how science is taughtthere, see:

Rau M (2010) Blind date in the sci-ence classroom. Science in School 17.www.scienceinschool.org/2010/issue17/wernerliese

To learn more about Geerat Vermeij’sresearch, see his latest book:

Vermeij GJ (2011) The EvolutionaryWorld: How Adaptation ExplainsEverything from Seashells toCivilization. New York, NY, USA:Thomas Dunne Books. ISBN:9780312591083

If you enjoyed this article, you maylike to browse the other scientistprofiles in Science in School:www.scienceinschool.org/scientists

Image courtesy of YinYang / iStockphoto



Ben Goldacre, writer, broadcast-er and doctor, is on a crusade: ascientific crusade – against

pseudoscience.Why should British teachers stop

using the Brain Gym, which refers toitself as an ‘educational movement-based model’ and is used in thou-sands of British schools? In BadScience, Ben Goldacre describes theBrain Gym as “a vast empire of pseu-doscience” that tells children “that ifthey wiggle their head up and downit will increase the blood flow to thefrontal lobes, thus improving concen-tration; … that there is no water inprocessed food; and that holdingwater on their tongue will hydrate thebrain directly through the roof of themouth”. In a sense, he acknowledges,the Brain Gym works: it encouragesregular breaks in lessons, light exer-cise and drinking plenty of water. Allgood – and effective – activities.

So what’s the problem? Accordingto Goldacre, this “transparent, shame-ful and embarrassing nonsense”poses two problems, which apply toall pseudoscience. First, you can blindpeople with scientific-sounding lan-guage and get them to do somethingintrinsically sensible, but is it ethicalto lie to them to achieve this? Second,by hiding common sense in scientific-sounding hocus pocus, you create aveil of mystery around science, pre-venting people from thinking forthemselves about seemingly scientificclaims or using the scientific knowl-edge they have.

Over the course of his book,Goldacre examines:

· The misleading but accurate claimsof the cosmetics industry (read theclaims carefully: do they simply –and truthfully – state that one ofthe ingredients can make your skinlook younger, or do they actuallyclaim that the cream containsenough of the ingredient to dothis?).

· How we test whether a treatmentworks (why is the ‘evidence’ forhomeopathy flawed? How can youdesign a fair test of a treatment?).

· Some fascinating research on theplacebo effect, how the results canexplain some of the claims of pseu-doscience, and how the placeboeffect could be used in convention-al medicine.

My only criticisms are minor. Thebook would benefit from a more care-ful editor, to correct some grammati-cal errors, improve some clumsy sen-tences and – more importantly –remove some leaps in logic or missinginformation. Also, I suspect that manyreaders will find statements like “youmay disagree, and you now have thetools to do so meaningfully” ratherpatronising.

Notwithstanding, Bad Science is awonderful book and appropriate for awide audience. Read it – please! Enjoyit, share it with your friends and col-leagues and above all, with your stu-dents. It’s simply written, funny andutterly compelling; I nearly missed atrain connection because I was soabsorbed in it. This book reminds us

what is wonderful about science – sci-ence is powerful, it’s great fun, andneedn’t even be difficult.

I’m not a teacher, but I do havesome suggestions for how you coulduse Bad Science in school. Give anindividual chapter, or part of a chap-ter, to your students to read: they’llenjoy it (particularly the bit aboutwhy teachers shouldn’t use the BrainGym in lessons) and it will encouragethem to question the world aroundthem.

Get your students to practice whatBen Goldacre preaches: exposingpseudoscience for what it really is.Why not ask the class to collect pseu-doscientific claims (e.g. from newspa-pers, the Internet, adverts) and dis-cuss them in class? Perhaps you couldhave regular ‘pseudoscience busting’lessons: why is a particular claim mis-leading? Could there be any truth init? If so, what could the real explana-tion be, and how could you set up anexperiment to test it? Perhaps yourstudents could even carry out theexperiment.

Finally, to read Ben Goldacre’sweekly newspaper column, visit theBad Science websitew1.

DetailsPublisher: Fourth Estate

Publication year: 2008ISBN: 9780007240197

Web referencew1 – Bad science:

www.badscience.net

Reviews


Bad science

By Ben GoldacreReviewed by Eleanor Hayes, Editor-in-Chief of Science in School



Www.instructables.com is awebsite that shows youhow to make all sorts of

weird and wonderful things, fromapple coasters to a z-bend hyper- hornet.

With this exciting website, you canaccess most of the information with-out registration. For this review, weregistered for free membership (youdon’t have to) and were sent a welcome message, followed by a personalised email from the‘Instructables Robot’, which tells you that there are “tons of awesomethings to see on Instructables”, andoffers a choice of browsing or a“guided tour”.

The guided tour really helped; wedid not really understand what thesite was about until we workedthrough it. The ‘home’ page does nottell you enough, but the tour certainlydoes. Through this, we learned thatInstructables is a web-based “docu-mentation platform” where “passion-ate people share what they do andhow they do it, as well as learn from,and collaborate with, others”. Thiswas still a little vague, and had wenot been prompted by pictures of allsorts of gadgets, we might have won-dered what we had wandered into. Alink to the “awesome people” whomake Instructables happen, reassur-ingly shows some fairly normal peo-ple, and, in the terminology of thesite, the “seeds of Instructables germi-nated” at the Massachusetts Instituteof Technology Media Lab in Boston,USA, with the site developing as aplace for sharing projects and helpingothers.

Instructables are step-by-stepdescriptions of things that peoplehave made, along with informationabout how they made them. As thesite says, they are “educational, inspi-rational, and often replicable”, and sothey could be useful for enhancingand enriching science, technology,engineering and maths subjects, inand out of the classroom. The con-tents are divided into a number ofsections, such as ‘Health’, ‘Outside’,‘Solar’ and ‘Technology’. The key-word-guided navigation leading tospecific collections of instructablesand information is not always intu-itive, but it can be helpful.

Some of the instructables are clearlyrather specialised, such as the dachs-hund wheelchairw1, made to help aninjured dog exercise during recovery,or fun-based, such as making a mer-maid tail for swimmingw2. Many otherideas, however, are very educational,and certainly many look both excitingand feasible for students to try them-selves, with suitable help as appropri-ate. This could be as a project or per-haps as extension and / or extracur-ricular activities, or even in cross-cur-ricular groups. The longer youbrowse the site, the more you find. Itseems to be a very active site, withnew material being constantly added.

For the physics classroom, there is a large variety of gadgets to be builtas teaching activities, such as a simple steam enginew3 or a Stirlingengine built from a crisp packagew4, a Savonius wind turbine built fromcardboardw5, a fifteen-minute self-propelled hovercraftw6 or a solar-powered LED-lighted sun jarw7.

More complicated projects include thebreath-powered USB chargerw8, build-ing a macro particle acceleratorw9 thatpropels a conductive ping pong ball,or creating a lighted star mapw10. Oryou may trick your students with thefake portable gravitation shieldw11 –very useful for teaching magnetics.

Whereas many of the instructablesfrom the ‘Technology’ and ‘Solar’ sec-tions are most appropriate for use inthe physics classroom, there are manyinteresting ideas for the other sci-ences, too: you could make lumines-cent silicone paintw12, grow silver crystalsw13 or build a ballistic soapbubble machinew14 in the chemistryclassroom. In Earth sciences, buildinga tsunami modelw15 with gutter segments could be fun; and in biology, you could grow oyster mushrooms in a coffee cupw16, havethe students build muscular anatomymodels with Halloween skeletonsw17,bake or sew a cell modelw18, w19, or, ifyou want to get seriously involved,build your own thermocycler forPCRw20.

The numbered steps for all theinstructables, or projects, ought tomake following the instructions easi-er, and the accompanying pictureslook as though they should help agreat deal. Some of the materials, e.g.“ultra-concentrated Dawn dish deter-gent (blue)”, might be hard to comeby outside the USA, but the greatthing about this site is that you canask about alternatives and are likelyto get a response from either the proj-ect maker or others who contribute tofeedback and discussions on the site.Suggestions for modifying projects


Instructables website

Reviewed by Sue Howarth, UK and Marlene Rau, Germany


are common, giving a strong sense ofuser involvement.

Obviously, teachers thinking ofusing any of the ideas need to trythem first and make sure that all thenecessary materials are to hand. It isuseful that approximate costs aregiven. Importantly to note is that theextent of the safety advice providedfor each project is variable, so a thor-ough risk assessment would be neces-sary before letting students start.

If all goes well, and students want afurther challenge, there is scope todesign their own instructable, and aguidew21 is provided to help with thisand to show how to upload it ontothe site.

In addition to step-by-step instruc-tions, the website offers photos andvideos of the gadgets, informativearticles on miscellaneous topics, con-tests amongst the users for uploadingthe best instructable on a given topic– such as the ‘Belt re-use challenge’ orthe ‘Homemade soup contest’, and avery active discussion forum, includ-ing a question-and-answer section.

Note: There is an option of signingup and paying for ‘pro’ membership,for USD 1.95 / month, billed annuallyor USD 39.95 for two years as a one-time payment. A membership com-parison list points out that signing upas a paid member would let youdownload PDFs, see instructions on asingle page, view less advertising,and generally help to support the site.Members also receive the newsletterand gain access to past newsletterarchives.

Reviews


Web referencesBelow are the links to the individual instructables mentioned in the article.

The URLs are fairly self-explanatory:

w1 – www.instructables.com/id/Dachshund-wheelchair

w2 – www.instructables.com/id/How-to-Make-A-Mermaid-Tail-for-Swimming

w3 – www.instructables.com/id/A-Simple-Steam-Engine-Anyone-Can-Build

w4 – www.instructables.com/id/The-amazing-pringles-tube-Stirling-engine

w5 – www.instructables.com/id/Cardboard-Savonius-turbine

w6 – www.instructables.com/id/Fifteen-Minute%2c-Self-propelled-hovercraft

w7 – www.instructables.com/id/Home-made-Sun-Jar

w8 – www.instructables.com/id/Breath-powered-USB-charger

w9 – www.instructables.com/id/How-to-make-a-macro-particle-accelerator

w10 – www.instructables.com/id/Star-Map

w11 – www.instructables.com/id/A-small-portable-gravitation-shield

w12 – www.instructables.com/id/Making-Ooglo-Luminescent-Silicone-Paint

w13 – www.instructables.com/id/Grow-Silver-Crystals-by-Electrochemistry

w14 – www.instructables.com/id/Make-a-Ballistic-Bubbles-Machine

w15 –www.instructables.com/id/Tsunami-Model

w16 – www.instructables.com/id/Gourmet-mushrooms-in-an-old-coffee-cup

w17 – www.instructables.com/id/Muscle-anatomy-with-Sugru-and-a-Halloween-skeleton

w18 – www.instructables.com/id/Plant-Cell-Cake

w19 – www.instructables.com/id/Plush-Cell-Model

w20 – www.instructables.com/id/Coffee-Cup-PCR-Thermocycler-costing-under-350

w21 – For instructions on how to create your own instructables, see:www.instructables.com/id/How-to-make-a-great-Instructable



Relativity is, admittedly, a diffi-cult subject to understand,even to science-oriented peo-

ple. In Relativity: A Very ShortIntroduction, Russell Stannard hasmade an effort to explain relativityand its implications for the laws thatgovern the Universe in a way that canbe understood by those with at leastsome basic knowledge of physics.The book is rich in scientific terminol-ogy, so a good knowledge of Englishis essential to understand it. Stannardhas also included a wealth of dia-grams and mathematical equations.These can make the book more diffi-cult to understand if the reader is notadequately trained in dealing withsuch information. But, there is analternative solution: ignore most ofthe diagrams and formulas and con-centrate only on the basic ideas pre-sented. Such casual reading will allowthe reader to filter out all the explana-tory details and keep the basicdescription of what relativity is allabout. Of course, if one is determinedto capture the full extent of relativity,this book provides an excellentopportunity for achieving this.

Regardless of the background andscope of the reader, he / she will berewarded in the last chapters of thebook with information on excitingsubjects, the type favoured by sciencefiction. The Big Bang, black holes,

worm holes, supernovas, the expand-ing Universe, dark energy and darkmatter are but a few of such issuesStannard has elaborated on andenables the reader to distinguishbetween science and imagination.

In school, there are a number of waysin which this book can be useful,especially in an advanced physics orastronomy class. Considering that thetheory of relativity is taught in sec-ondary schools across the world,teachers can use the book to drawbasic information on the theory itself,but more importantly, to informthemselves and their students on thelatest theories regarding the natureand the peculiarities of the Universe.Students might find it very difficult toread and understand the entire book,but if they concentrate on specific sec-tions of the book, with a little helpfrom their physics teacher, they willbe able to benefit greatly from it.Along those lines, the teacher couldassign projects to his students thatwould require more careful study ofspecific sections of the book.

The book is also available in aGerman translation.

DetailsPublisher: Oxford University Press

Publication year: 2008ISBN: 9780199236220


Relativity: A Very Short Introduction

By Russell StannardReviewed by Michalis Hadjimarcou, Cyprus



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