Magnetism - Science A-Z

www.readinga-z.com

MagnetismMagnetism

A Reading A–Z Level P Leveled BookWord Count: 1,170

Visit www.readinga-z.com for thousands of books and materials.

Written by Elizabeth AustinIllustrated by John Kastner

LEVELED BOOK • P

Written by Elizabeth AustinIllustrated by John Kastner

MagnetismLevel P Leveled Book© Learning A–ZWritten by Elizabeth AustinIllustrated by John Kastner

All rights reserved.

www.readinga-z.com

Photo Credits:Front cover, page 20: © RubberBall/RubberBall/SuperStock; back cover, pages 3, 4 (top left), 4 (bottom center), 4 (bottom right), 11, 14,16: © PhotoSpin; title page, page 6: © Jovani Carlo Gorospe/123RF; pages 4 (top center), 17: © Amos Morgan/Photodisc/Getty Images; page 4 (top right): © Ryan McVay/Photodisc/Getty Images; page 4 (bottom left): © Photodisc; page 5: © Science Photo Library/Science Photo Library/SuperStock; page 7: Courtesy of NASA/JPL; page 9: © Arthur S. Aubry/PhotoDisc/Getty Images; page 10: © Learning A-Z; page 13: © Richard Gross/Corbis; page 19: © Draguta/Dreamstime.com

www.readinga-z.com

Magnetism

CorrelationLEVEL P

M2828

Fountas & PinnellReading Recovery

DRA

3 4

Table of ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . . . 4

Magnetism and Magnets . . . . . . . . . . . . 5

Magnetic Field . . . . . . . . . . . . . . . . . . . . . 8

How Are Magnets Made? . . . . . . . . . . 10

Try This . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Magnetism and Electricity . . . . . . . . . . 13

Using Magnetism . . . . . . . . . . . . . . . . . 16

Conclusion . . . . . . . . . . . . . . . . . . . . . . . 20

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . 21

IntroductionLook around your home and try to find a magnet . A magnet is a metal object that sticks to other metals . You might have some magnets among your toys . There are probably magnets on your refrigerator . But did you know that there may be hundreds of magnets in your home? You cannot see most of them . But they are inside your television, telephone, and stereo . They are inside electric motors that power your blender and hair dryer . Computers are full of magnets . And all the electricity that runs these things comes from magnetism .

Magnetism • Level P

5 6

Magnetism and MagnetsMagnetism is an invisible force . A force is anything that pushes, pulls, or moves an object . Magnetism is a special force that only pulls on some metals, such as iron . A magnet will not push or pull plastic or tin .

Magnetism flows in one direction through a magnet, no matter what shape the magnet is . It flows in one end and out the other . The ends of a magnet are called

magnetic poles . Every magnet has a north and a south pole . The force flows out the north pole and back in the south pole .

You can use two magnets to feel magnetism flowing . The north pole of one magnet will stick to the south pole of the other . Now, try to push the two north poles together . It feels almost like trying to connect two hoses that are both spraying water . The magnetic force pushes the north poles apart, because the magnetic forces are flowing against each other . Two north poles will always repel each other . So will two south poles .


7 8

The Earth’s iron core is magnetic . The whole planet acts like a giant magnet . If you dangle a magnet by a string, one pole will point north and the other will point south . This is exactly how a compass works . This gave the north and south poles of a magnet their names .

Magnetic FieldThe magnetic force flows out the north pole of the magnet . Then, it loops around outside the magnet and flows back in the south pole . Magnetism flows through space in lines of force . The invisible shape formed by the lines of force around the magnet is called the magnetic field .

Do You Know?Earth’s north and south magnetic poles are

not quite at the true North and South Poles. The

north magnetic pole is in northern Canada. The

south magnetic pole is in the Pacific Ocean south

of Australia. Since Earth’s core moves around,

the magnetic poles move, too. They can even flip

completely around. If this happened today, your

compass needle would point south!


9 10

Any iron or other magnets inside a magnetic field will be pulled toward the magnet . Stronger magnets have more lines of force and larger magnetic fields .

To see a magnetic field, place a magnet on a piece of paper . Sprinkle iron filings around the magnet . The filings will gather along the lines of force in the shape of the magnetic field .

How Are Magnets Made?The first magnets were made of a natural rock called lodestone . People used pieces of lodestone in compasses . But they did not know how they worked .

Every material is made of extremely tiny

pieces called atoms . Most atoms spin . This

spinning creates a tiny, tiny force . In

most things, like rocks or plastic, the atoms

spin every which way . The tiny forces never add up . But when something becomes magnetized, the atoms spin in the same direction . All the tiny forces add up to create a magnetic force . Eventually, people learned how to line up the atoms in some metals to create new magnets .


11 12

Some things, such as iron, become magnetized more easily than others . A piece of ordinary iron is placed inside a strong magnetic field . The magnetic force makes the iron atoms line up and spin in the same direction . This makes a new magnet . The more atoms that spin in the same direction, the stronger the magnet becomes . Sometimes if you drop a magnet, some of the atoms get knocked out of line, and the magnet gets weaker .

Make your own magnet! You will need a large iron nail,

a strong magnet, and several paper clips.

1 Hold the nail by one end and slide it across the magnet in one direction. Keep sliding it over and over. The magnet’s lines of force will start to line up the atoms in the nail.

2 After 20 to 30 times, touch the nail to the paper clips. Does the nail pick up the clips? How many can it pick up at once? Keep stroking the nail along the magnet to make the nail’s magnetic force stronger. See if you can pick up all the paper clips at once.

Try This


13 14

Magnetism and ElectricityMagnetism and electricity are very closely related . Magnets can make electricity . And electricity creates magnetic fields . This is because both magnetism and electricity affect the way atoms spin .

All the electricity you use comes from machines called generators . Generators make electricity by spinning magnets around coils of wire . The magnetism creates an electric current in the wire . The difficult part is getting the magnets spinning . Power plants use running water, wind, or steam from burning fuel to turn the magnets .

electric current

turning magnet

wirecoil

Generator


15 16

Electricity can create special magnets called electromagnets . A wire is wrapped around a regular piece of iron . Then an electric current from a battery or outlet flows through the wire . The electric current makes a magnetic field . This magnetizes the iron . But the iron only stays magnetized as long as the electricity is on .

Using MagnetismThe earliest use of magnetism was the compass . A small, freely moving magnetic needle pointed to Earth’s magnetic north pole . This helped guide travelers and explorers . Modern travelers still use compasses .

Electricity comes from spinning magnets inside generators . And electric motors work like generators in reverse . They use electric current to spin magnets . The magnets are attached to fans, cutting blades, or wheels . This is how fans, blenders, and remote-control cars work .

electric currentiron bar

wire coil

Electromagnet


17 18

Magnets can also encode information, or store it in a special code . Cassette tapes, videotapes, computer disks, and credit cards all use strips of tiny magnets . The magnets are the size of grains of powder . There can be millions of magnets on one tape, disk, or credit card . Each tiny magnet points in its own direction . The different positions of the magnets create a code . Tape players, VCRs, and computers sense the tiny magnetic fields and read the code . Putting a credit card, tape, or disk near a powerful magnet can mess up or erase the code .

Some high-speed trains run on electromagnets . The trains have powerful electromagnets on the bottom . The track also has powerful electromagnets . The two electromagnets face each other so that they repel each other . The magnetic force is so strong that it lifts the train off the track . The train floats above the track . It actually flies as it travels . This makes a fast, smooth ride .


19 20

Special machines called MRIs can look inside a person’s body . The person lies inside a tube cut right down the center of a very powerful magnet . The lines of force flow through the person’s body . The magnetism is so strong that it causes the atoms in the body to spin in the same direction . Special sensitive instruments can tell how fast the atoms spin . Computers figure out what kind of atoms they are based on how they spin . This gives doctors an idea of what is going on inside a person’s body .

Doctors can find atoms that are not supposed to be there . They can see cancer and other diseases . MRIs give doctors a look inside the body without having to cut the body open .

ConclusionWhile magnets may seem simple, there is no end to their uses . Every time you watch a tape, turn on the air conditioner, or even turn on a light, you are using magnets . Someday you may ride on a high-speed train or use an MRI . Playing with magnets can be lots of fun . The magnetism you play with is the same force that has made modern life possible .


21 22

Glossaryatoms the smallest parts of an

element(p . 10)

electro- temporary magnets magnets made by passing an

electric current through a wire wrapped around a piece of iron (p . 15)

encode to put information in a special code (p . 17)

force the strength or energy that moves objects (p . 5)

generators machines that create electricity in coils of wire using spinning magnets (p . 14)

lines of force invisible lines of magnetic force that flow through and around a magnet (p . 8)

lodestone naturally magnetic rock (p . 10)

magnetic able to attract certain metals, such as iron (p . 7)

magnetic invisible shape of the field lines of force around

a magnet (p . 8)

magnetic the ends of a magnet poles where the magnetic force

flows in and out (p . 5)

magnetism a force that pushes and pulls certain metals (p . 4)

motors machines that turn electricity into motion using coils of wire to spin magnets (p . 16)

repel force away (p . 6)


FOCUS Book

Beyond the BookVisit a museum or go online to learn about Van de Graaff generators.

Make predictions about which objects can make static electricity. Gather a balloon and items to test.

Blow up the balloon. Find out which objects stick to it.

Create static electricity using the balloon. Predict which objects will stick to the balloon now. Test each object. Write or draw what you observe.

Static Electricity © Learning A–Z Written by Cynthia Kennedy Henzel

All rights reserved.

www.sciencea-z.com

Photo Credits: Front cover: © Image Source/Corbis; pages 2 (left), 3 (top right): © scanrail/iStock/Thinkstock; page 2 (center): © ivansmuk/iStock/Thinkstock; page 2 (right): © Grassetto/iStock/Thinkstock; page 3 (top left): © Diabluses/iStock/Thinkstock; page 3 (bottom): © Travis Manley/123RF; page 5: © Richard Haines/iStock/Thinkstock; page 7: © sytilin/iStock/Thinkstock; page 8: © CandiceDawn/iStock/Thinkstock

Illustration Credits:Pages 6, 9: Signe Nordin/© Learning A–Z

2

Electricity lights up lamps. It powers your TV. It keeps your food cold. You use electricity every day.

Electricity is a kind of energy, or power.

The electricity used in homes is called electric current. It flows through wires to power things in your house.

You Use Electricity

What is static electricity, and how does it occur?

Cause and Effect

FOCUS Question

TVs, lamps, and refrigerators all run on electric current.

A current of water and a current of electricity both flow. They move along in a steady way.

Reading Levels

Learning A–Z K

Lexile 540L

Correlations

Fountas and Pinnell* J

*Correlated independent reading level

Energy • Static Electricity 3 4

Flashlights also use electric current. The power comes from a battery.

Look at the ends of a battery. One end is positive, and one end is negative. These are called charges. Negative charges move toward positive charges. This makes an electric current flow.

Static electricity does not flow in a current. It stays on the outside of an object. Static forms when there is a positive or negative charge.

Rub a balloon on your hair. Now the balloon sticks to a wall. Why?

You gave the balloon a negative charge from your hair. The wall has a slightly positive charge when the balloon is near it.

The positive and negative charges pull together. The balloon sticks to the wall.

Sticky Balloons ElEctricity from a BattEry

A positive and negative electrical charge pull together. But two negative or two positive charges push each other apart.

Flashlights, computers, tablets, phones, and cars all use batteries.


Run a comb through your dry hair. Each strand sticks up! Why?

Two positive charges push away from each other (see page 4). The comb left your hair with positive charges of static electricity. Each strand pushes away from the others, so they stick up.

If too much static electricity builds up on an object, it jumps to another object.

Want to try it? Put on socks. Then rub your feet on a carpet. You’re building up a negative static charge.

Now touch a metal doorknob. Zip! The shock you feel is the negative charge jumping quickly from you to the doorknob. You may even see a spark.

A Little ShockBad Hair Day


Lightning is static electricity in a big way! The powerful spark quickly jumps between clouds or between a cloud and the ground.

Zap!! That is one dangerous spark of static electricity.

Static electricity can be helpful.

Machines called scrubbers use static electricity to clean dirty air. Filters with positive charges pull bits of smoke and dirt out of the air. Cleaner air comes out!

Copy machines also use static electricity. It makes ink stick to the right places on the paper.

Using Static ElectricityA Big Shock

When smokestacks use scrubbers, steam and cleaner air come out.

Negative charges in a cloud move toward positive charges on the ground. This makes lightning.

Lightning strikes the ground in the United States about 38 times per minute.


Rub your feet on a carpet again. You will build up a small negative charge. Instead of touching a doorknob this time, touch a friend.

At least one of you will get a charge out of it!

Write or draw your answers on separate paper. Use details from the book to support each answer.

1 According to the book, what is the difference between electric current and static electricity?

2 Why does hair stand up when it is charged with static electricity?

3 Think about the headings the writer used on pages 6 and 7. How do these headings help explain the difference between a doorknob shock and lightning?

4 Look at the picture of the smokestack on page 8. How might the picture look different if this factory did not use static electricity?

What is static electricity, and how does it occur? Imagine that your friend asks you what causes the kind of shock described in this book. Use your own words to explain the answer.

FOCUS Question

Safe Fun with Static

1© Learning A–Z All rights reserved. www.sciencea-z.com

Name Date

Forces at a Distance

Lesson 3

Part 1: Ask QuestionsLook at each picture. Then circle the question that you could investigate using the objects shown. The question should also help you learn about how magnets work.

2.

How many paper clips can a magnet pick up?

At which distance will a magnet attract a paper clip?

How much longer is the magnet than the paper clip?

Are all magnets made of the same kind of material?

Are the two magnets the same size?

Do opposite poles of magnets attract or repel?

1.

cm

S N magnet

S N S N

Magnet 1 Magnet 2

paper clip

ruler

Storyline Assessment


Name Date


Lesson 3

Part 2: Use the Diagram Draw a magnetic field around the magnet. Circle YES or NO to answer each question and then complete the claim.

1. Will the paper clip move toward the magnet if it is outside the magnetic field?

YES NO

2. Will the paper clip move toward the magnet if it is inside the magnetic field?

YES NO

3. Will the eraser move toward the magnet if it is outside the magnetic field?

YES NO

4. Will the eraser move toward the magnet if it is inside the magnetic field?

YES NO

Write a claim using the evidence above to explain what causes a magnet to attract an object.

paper clip

eraserS N



Name Date


Lesson 3

Part 3: Compare the ForcesComplete the Venn diagram to compare how magnetism and static electricity are similar and different. Write at least one thing about each force on the sides of the diagram. In the center, write how the two are similar.

Magnetism Static ElectricityBoth


ANSWER KEY AND TEACHING TIPS


* Next Generation Science Standards is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards was involved in the production of, and does not endorse, this product.


Lesson 3

Connections to the Next Generation Science Standards*Target Science and Engineering Practice: Asking Questions and Defining Problems• Ask questions that can be investigated based on patterns such as cause and effect relationships.

Associated Performance Expectation: 3-PS2-3. Ask questions to determine cause and effect relationships of electric or magnetic interactions between two objects not in contact with each other.

All questions in this assessment relate to the Disciplinary Core Ideas DCI of this Performance Expectation. Look for the SEP and CCC symbols for questions that specifically address Science and Engineering Practices and Crosscutting Concepts.

SummaryStudents identify testable questions, demonstrate an understanding of how a magnet’s magnetic field can affect different objects, and compare magnetism and static electricity, recognizing that both forces can influence objects at a distance.

Part 1: Ask Questions1. �At which distance

wil l a magnet attract

a paper clip?

2. �Do opposite poles

of magnets attract

or repel?

Part 2: Use the DiagramStudents should draw a magnetic field around the magnet by adding lines of force that exit the north pole, circle around the magnet, and re-enter at the south pole. Many diagrams, including this example, show partial lines of force that extend beyond the scale of the diagram before returning to the south pole. But this feature is not required in student diagrams.

1. NO

2. YES

3. �NO

4. �NO

A�magnet’s�magnetic�field�attracts�some�objects,�such�as�paper�clips,�and�causes�them�to�move�toward�the�magnet.�The�object�has�to�be�made�of�a�certain�kind�of�metal�and�be�inside�the�magnetic�field�in�order�to�move.�The�eraser�won’t�move�even�if�it�is�inside�the�magnetic�field�because�it�is�not�made�of�metal.�

SEP

SEP

CCC

S N


Storyline Assessment Forces at a Distance

Lesson 3

Part 3: Compare the ForcesResponses may vary, but students should note that magnetism involves a magnetic field and that static electricity works by way of charges that build up on the outside of objects. The two forces are similar in that they can affect objects at a distance without actually coming in contact with them.

Photo credit: page 1: © iStock.com/dragance137

Illustration credits: all: © Learning A–Z

Teaching TipsIf students have trouble performing the tasks on this assessment, ask them to look back at the questions they wrote during Lesson 3 and the results of their investigation. Remind them of the importance of writing questions that are based on observations and that are testable. Explain that permanent magnets have a magnetic field, which can push or pull certain metals. The magnetic field extends beyond the magnet itself and can therefore exert a force at a distance. Refer back to the diagram on page 8 of the Magnetism Reading A–Z Leveled Book if students need help drawing a magnetic field around the magnet. Discuss that magnets only affect other magnets and objects made of certain kinds of metal. Also, review with students that gravity, magnetism, and static electricity are all forces that can affect objects without coming in direct contact with them, but these forces are also different in important ways.

ExtensionsFor students who complete their work early or are ready for an extra challenge, assign additional resources related to this topic found on the Grade 3 Forces and Interactions NGSS page on Science A–Z.

needs�a�magnetic�field

only�works�on�some�metals

can�push�or�pull�(attract�or�repel)

can�affect�objects�without�touching�them

needs�charges�on�the�outside�of�objects

works�on�hair,�fabric,�and�other�materials

Magnetism Static ElectricityBoth

https://www.sciencea-z.com/main/NextGenerationScienceStandards/from_ngss_resource_menu/true/ngss_topic_id/10

Magnetism - Science A-Z

Documents

Transcript of Magnetism - Science A-Z