Earth’s Systems and Cycles

Examine Earth from a new perspective

 http://www.classzone.com/books/earth_science/terc/content/visualizations/es0101/es0101page01.

Earth as a System

 A system is a part of the universe that can be studied separately.

 Scientists sometimes study individual parts of the Earth such as:  How mountains form  Classification of life forms  How tornadoes form

Today we understand that the all parts of the Earth are connected and interacting

The best way to understand the Earth is not to study the parts in isolation but as one system

Closed vs. Open Systems

Closed Systems Open Systems

Matters does not enter or leave

Matter enters and leaves

Energy enters and leaves Energy enters and leaves

Earth is a Closed System Energy from the sun is

absorbed by the Earth’s atmosphere and surface during the day

Energy is lost back into space at night

The matter on Earth is the same matter that was here when Earth formed.

Matter changes form but the amount of matter remains the same.

Mt Etna lava picture source: :http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17479

How is a jar of sun tea like the Earth?

 Sun tea is made with tea bags and water in a closed jar that is left out in the sun.

 How is this similar to Earth as a closed system?

Except….

What happens when a meteorite hits Earth? A tiny amount of Hydrogen atoms are lost to space.

Overall, Earth is still considered a closed system.

This means our resources must be conserved and protected.

Earth’s system includes 4 spheres that interact

  The Atmosphere consists of the gases that surround the Earth   The Geosphere (also called lithosphere) consist of the rocks,

minerals, soils, ocean basins and Earth’s interior   The Hydrosphere includes the water in oceans, rivers,

groundwater, clouds, lakes, ice caps and glaciers   The Biosphere includes all things living or coming from living

things.   Visualize Earth’s spheres:

http://www.classzone.com/books/earth_science/terc/content/visualizations/es0102/es0102page01.cfm?chapter_no=visualization

Earth’s Sphere’s Interact

 An erupting volcano releases lava, volcanic bombs (geosphere) and gases and ash into the air (atmosphere), the animals are suffocated (biosphere), plants burn up (biosphere), ash flows fill rivers (hydrosphere).

http://volcano.und.edu/vwintl/vwintl.html

More interaction examples

 Plants and animals take in oxygen from the atmosphere and release carbon dioxide.

 People remove plants, release chemicals into the air and water

 How does using cars show interactions between spheres?

Car exhaust. © NMM London

Cycles involve interactions between the spheres

A cycle is a event or process that repeats over and over again. Examples: The water cycle The carbon cycle The nitrogen cycle

A biogeochemical cycle moves nutrients between living and nonliving portions of the Earth

http://www.windows.ucar.edu/tour/link=/earth/Water/co2_cycle.html&edu=mid

The Water Cycle   Water leaves the oceans and

other bodies of water through evaporation and the leaves of plants through transpiration.   Solar energy powers this

part of the water cycle.   Water vapor cools and

condenses to make cloud droplets or ice crystals that merge to form rain and other forms of precipitation.  Gravity pulls the

precipitation back down to the surface.

See U.S.G.S for a quick summary: http://ga.water.usgs.gov/edu/watercyclesummary.html

Precipitation can be rain, snow, sleet or hail

 Precipitation falls to the Earth  and either infiltrates

into the ground,  becomes runoff that

moves across the surface,

  lands in a body of water   or is evaporated back

up into the sky

 Can you label A - G? Rita Haberlin’s Lecture notes: http://members.aol.com/rhaberlin/hcpptnts.htm

We Impact the Water Cycle

Developing land reduces the amount of water that can sink into the ground, infiltration and increases the amount of runoff that occurs.

This causes other problems such as: Soil erosion Loss of ground water recharge Flooding Pollution of lakes and streams

Judith Earl slideshow: http://managingwholes.com/photos/erosion/pictures/slide17.html

The Carbon Cycle   Carbon is the basic element

found in all living organisms   Carbon is also found:

  in rocks (carbonates) and shelled organisms

  dissolved in water (carbon dioxide and carbonic acid

  in the atmosphere (carbon dioxide)

Windows to the Universe: The Carbon cycle: http://www.windows.ucar.edu/tour/link=/earth/Water/co2_cycle.html&edu=high

The Carbon Cycle continued   Plants take in carbon dioxide

from the atmosphere to make sugars in photosynthesis

  Animals get their carbon by eating plants or through food chains

  Plants, animals and some bacteria absorb oxygen and release carbon dioxide through respiration

  Death and decay of organisms releases carbon into the soil

Humans and the Carbon Cycle

  Fossil fuels such as coal forms when peat moss and other dead organisms are buried deep within the earth for millions of years

  We burn the fossil fuels through the process of combustion and release the stored carbon as carbon dioxide into the atmosphere again.

  Scientists are concerned that increased carbon dioxide levels in our atmosphere is causing global warming.

http://www.windows.ucar.edu/tour/link=/earth/climate/cli_gallery.html&edu

The Nitrogen Cycle   Nitrogen is the most

abundant gas in our atmosphere (78%)

  Nitrogen is an essential plant nutrient  As is phosphorus and

potassium   Bacteria convert nitrogen to

nitrates and ammonia which plants can absorb from the soil

  Animals get the nitrogen they need to build proteins and other important molecules by eating plants or other animals http://www.windows.ucar.edu/tour/link=/earth/Life/nitrogen_cycle.html

The Nitrogen Cycle continued  There are also bacteria

that release Nitrogen gas into the air

 Manure from animals, human sewage and chemical fertilizers all add nitrogen to the soil and water

 Excess nitrogen in water causes algae blooms and can lead to the premature aging and death of a lake due to lack of oxygen

Phytoplankton blooms create a dead zone in the Gulf of Mexico: http://www.windows.ucar.edu/tour/link=/earth/climate/nitrogen_fertilizer.html

Energy  The primary source of energy for the Earth is the sun  Energy cannot be created or destroyed in ordinary

reactions, only changed from one form to another. (First Law of Thermodynamics)

 Exceptions to this law are nuclear reactions, fission and fusion  Nuclear reactions do create large amounts of

energy from small amounts of matter  Example - solar power is created through the

fusion (combining) of 4 hydrogen atoms into 1 helium atom

Examples of the energy changing forms

 Food chains are examples of energy changing form  Solar energy is trapped by pigments in plants  This is converted to chemical energy stored in the bonds

of sugars  Animals that eat the plants obtain chemical energy

 Chemical energy stored in gasoline is released in your car through combustion  This turns to mechanical energy to allow your car to

move   Another way to state this law is

 You can’t make something from nothing  We cannot create energy

Energy changing form

http://www.ftexploring.com/energy/energy-1.htm

Second Law of Thermodynamics

 When energy changes form, it becomes less and less useful.  Most of it is lost as heat

 In other words, you can’t make something from nothing…

 You can’t even break even

http://www.ftexploring.com/energy/2nd_Law.html