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Earth Systems.

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Presentation on theme: "Earth Systems."— Presentation transcript:

1 Earth Systems

2 Things to think about Look at the world map
Earth’s surface is not smooth. What do you think causes variations in its surface? Is the Earth changing? List any evidence (features or processes) that it is or is not changing. What changes might occur to Earth’s surface On a time scale of 100 years On a long time scale (10,000 – 1,000,000s)

3 USGS recent earthquakes
The above link is to recent earthquakes

4 What does the pattern of earthquakes and volcanoes suggest?
How about the shape of the continents?

5 Tectonic plates

6 Animation: breakup of pangea

7 Structure of the Earth

8 Heat: where did it (does it) come from?

9 How do scientists know about the Earth’s structure?
One way: earthquake waves that pass through the Earth and over the Earth’s surface P waves (compressional, primary) S waves (shear, secondary) Model

10 Plate boundaries

11 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 swim—or they are freshwater animals—so the continents must have been connected

12 Convection in the mantle
Show the mantle model

13 Sea-floor spreading Mid-ocean ridge Diverging plate boundary
How do we know? Prediction about age of sea floor Magnetic reversals It’s still spreading!

14 What does it mean… To refer to the Earth as a system?
Think ``machine’’ versus ``parts’’

15 Parts of the earth system
Lithosphere (geosphere) Hydrosphere Atmosphere Biosphere

16 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?

17 Hydrosphere


19 What happens to water With one partner, sketch out where you think water goes. Start with water in the ocean.


21 Water cycle Nasa's water cycle movie

22 Ocean water 96.5 % H2O 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

23 Salinity patterns number is “parts per thousand”

24 Ocean currents Water flows horizontally Causes?
Surface: wind Deep: density differences – salinity, temperature Ocean conveyor - YouTube

25 Vertical movements Upwelling
Deep, cold water rises to replace surface waters that flow away Brings nutrients to surface Site of rich fisheries

26 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%

27 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.

28 See All the Water in the world, Google Earth

29 Aquifer

30 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

31 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 key—the infiltration of water back to the aquifer

32 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 doesn’t prevent the ``coffee’’ from going through



35 What is this picture?



38 >97% of the water flowing into Lake Mead comes from snow melt and rain—runoff—in the Rocky Mts, the source of the Colorado R.

39 Lake Mead


41 Lake Mead water levels

42 US drought monitor

43 The atmosphere

44 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 O2, but H2O, CO2, CH4, HCl

45 Composition Nitrogen – 78 % Oxygen – 21 % All the rest???
Carbon dioxide, methane, CFCs, Water vapor is variable, from 0 to %

46 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

47 Impact of air density Where is air densest? Where is it least dense?
How does this affect a batted baseball?

48 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.

49 Troposphere Our sphere Weather Notice: patterns
Temperature Winds Layer ends when temp. no longer varies with height = tropopause

50 Water cycle Connects ocean and atmosphere Key pt: what happens in the atmosphere depends a lot on what happens in the ocean

51 Solar energy Energy from sun Some absorbed by gases (O3, H2O)
Some reflected by clouds and by the Earth’s surface Last is called albedo

52 albedo Notice snow, water, and clouds
What feedback effects would you expect from melting of ice caps?

53 Energy transfer

54 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

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