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