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