Presentation on theme: "Earth Systems. Things to think about Look at the world map 1.Earths surface is not smooth. What do you think causes variations in its surface? 2.Is the."— Presentation transcript:
Things to think about Look at the world map 1.Earths surface is not smooth. What do you think causes variations in its surface? 2.Is the Earth changing? List any evidence (features or processes) that it is or is not changing. 3.What changes might occur to Earths surface 1.On a time scale of 100 years 2.On a long time scale (10,000 – 1,000,000s)
USGS recent earthquakes Recent Earthquakes –The above link is to recent earthquakes
What does the pattern of earthquakes and volcanoes suggest? How about the shape of the continents?
Animation: breakup of pangea ence/terc/content/visualizations/es0806/es 0806page01.cfm?chapter_no=visualizatio nhttp://www.classzone.com/books/earth_sci ence/terc/content/visualizations/es0806/es 0806page01.cfm?chapter_no=visualizatio n
Structure of the Earth
Heat: where did it (does it) come from?
How do scientists know about the Earths structure? One way: earthquake waves that pass through the Earth and over the Earths surface –P waves (compressional, primary) –S waves (shear, secondary) Model
More evidence of continental drift The colored bands represent where fossils of different critters and plants have been found. They span two or more continents. These creatures do NOT swimor they are freshwater animalsso the continents must have been connected
Convection in the mantle ence/terc/content/visualizations/es0805/es 0805page01.cfm?chapter_no=visualizatio nhttp://www.classzone.com/books/earth_sci ence/terc/content/visualizations/es0805/es 0805page01.cfm?chapter_no=visualizatio n Show the mantle model
Sea-floor spreading Mid-ocean ridge Diverging plate boundary How do we know? 1.Prediction about age of sea floor 2.Magnetic reversals 3.Its still spreading!
What does it mean… To refer to the Earth as a system? Think ``machine versus ``parts
Parts of the earth system Lithosphere (geosphere) Hydrosphere Atmosphere Biosphere
Open vs closed system Open: exchanges energy, matter, and/or information with other systems Closed: isolated and self-contained Is the Earth open or closed? –Energy? –Matter?
What happens to water With one partner, sketch out where you think water goes. Start with water in the ocean.
Water cycle Nasa's water cycle movie
Ocean water 96.5 % H 2 O by mass Remainder: various salts [35 parts per thousand] Temperature: –Warmer near the surface –Deep water (below ~1000 m) is equally cold Density: –Colder, saltier water is denser = deep water
Salinity patterns number is parts per thousand
Ocean currents Water flows horizontally Causes? –Surface: wind –Deep: density differences – salinity, temperature Ocean conveyor - YouTube
Vertical movements Upwelling –Deep, cold water rises to replace surface waters that flow away –Brings nutrients to surface –Site of rich fisheries
Freshwater Review: Where is the freshwater on Earth, and in approximately what percentages? –Ice caps, glaciers: 69 % –Aquifers:30 % –Surface water:0.9% –Atmosphere (and biosphere) :0.1%
Aquifers Rock layers below the surface of the earth that are porous and hold water. Water moves through an aquifer just as water moves in a river.
See All the Water in the world, Google Earth
How water moves in aquifers In a word: –SLOWLY! Depends on the size of the pore spaces. –Smaller spaces mean slower flow At the other extreme: Large ``pore space of a cave might have a river run through it
Aquifers Supply drinking water Anyone who has a well gets water from an aquifer About HALF of all Americans get most of their water from wells RECHARGE is keythe infiltration of water back to the aquifer
Aquifers Is the water clean? Water moving through pore spaces of rock or gravel is naturally filtered –``coffee filter keeps coffee grounds behind Dissolved chemicals can contaminate an aquifer and water pumped from its wells. –The filter doesnt prevent the ``coffee from going through
What is this picture?
>97% of the water flowing into Lake Mead comes from snow melt and rainrunoff in the Rocky Mts, the source of the Colorado R.
Lake Mead water levels es/http://www.arachnoid.com/NaturalResourc es/
US drought monitor mlhttp://www.drought.unl.edu/dm/monitor.ht ml
Where did the atmosphere come from? May have developed from gases released by volcanoes. This is Kilauea in Hawaii. Early atmosphere very different from today. NO O 2, but H 2 O, CO 2, CH 4, HCl
Composition Nitrogen – 78 % Oxygen – 21 % All the rest??? –Carbon dioxide, methane, CFCs, Water vapor is variable, from 0 to 4 %
Structure 4 major layers Troposphere: where the weather is Tropopause: jet stream Stratosphere: ozone layer 99% of the total mass of the atmosphere is below 32 km Temp. drops 5-10 C every 1 km in troposphere
Impact of air density Where is air densest? Where is it least dense? How does this affect a batted baseball? seball/homerun.htmlhttp://profhorn.meteor.wisc.edu/wxwise/ba seball/homerun.html
NOT true any longer: air conditioners and refrigerators no longer contain CFCs BUT: CFCs last a long time in the atmosphere (decades) so these gases are still doing damage.
Troposphere Our sphere Weather Notice: patterns –Temperature –Winds Layer ends when temp. no longer varies with height = tropopause
Water cycle Connects ocean and atmosphere Key pt: what happens in the atmosphere depends a lot on what happens in the ocean
Solar energy Energy from sun Some absorbed by gases (O3, H2O) Some reflected by clouds and by the Earths surface Last is called albedo
albedo Notice snow, water, and clouds What feedback effects would you expect from melting of ice caps?
Energy transfer Simplified earth: slow rotation to east, no interaction of oceans and land Sun warms equator, air rises, spreads north and south Cold air at poles sinks and replaces Air deflected by rotation, to right in N hemisphere, to left in S hemisphere –Coriolis effect