1. How The Earth Works

2. Earth: Basic Facts 150 million km from Sun (93 million miles) Diameter, just under 13,000 km (8,000 mi.) Density: 5.5 g/cc (5500 kg/m 3 ) –About twice as dense as surface rocks –Earth has a dense core Unique Features –Liquid Surface –Plate Tectonics –Life

3. Earth Systems

12. The Solid Earth

13. Earth Systems External Effects (Astronomical) Atmospheric Circulation Oceanic Circulation Hydrologic Cycle Rock Cycle Plate Tectonics

14. Convection

15. Earth and the Universe Rotation (Day-Night) Lunar (Tides) Annual (Seasons) Precession and Orbit Variations (Ice Ages?) Galactic (250 m.y. period) Unpredictable Events –Nearby Supernovae –Meteor Impacts Long-Term Evolution of Sun

16. The Atmosphere 79% Nitrogen, 20% Oxygen, 1% Argon Oxygen made by life –Example: glucose C 6 H 12 O 6 –6H 2 O + 6CO 2  C 6 H 12 O 6 + 6O 2 Greenhouse effect –Infrared absorbed by molecular vibrations –90% of earth’s greenhouse effect due to water vapor –Without a greenhouse effect, earth would be frozen

17. Atmospheric Circulation Unequal Solar Heating –Equator to Pole –Day - Night –Different Surfaces Buoyancy Adiabatic Heating and Cooling Coriolis Effect High and Low Pressure Fronts and Air Masses

18. Not a Manifestation of the Coriolis Effect! Too small scale for the Coriolis Effect to be significant

19. Atmospheric Circulation

20. Oceanic Circulation Surface Currents - Driven by Winds Thermohaline - Deep Circulation –Evaporation makes water more saline and denser –Freezing makes water more saline and denser –Cold water is denser than warm water

21. Surface Currents

22. Thermohaline Circulation

23. Hydrologic Cycle Evaporation from Oceans Precipitation on Land –Infiltration into Ground (Ground Water) –Runoff (Erosion)

24. Hydrologic Cycle

25. Water Principal Agent in Modifying Earth’s Surface Medium for Storing and Distributing Global Heat The Universal Solvent –Essential for Life –Destructive to Rocks Lowers Melting Point of Rocks Reduces Strength of Rocks Under Pressure

26. The Rock Cycle New Rocks Exposed by Erosion Rocks Broken Down Mechanically and Chemically (Weathering) Components Transported by Erosion Components Cemented into Sedimentary Rocks Burial and Heating creates Metamorphic Rocks Melting Creates Igneous Rocks

27. The Rock Cycle

28. Plate Tectonics Outer Crust of Earth Moves a Few cm/yr Driven by Convection in Earth’s Interior Accounts For: –Earthquakes –Volcanoes –Mountain-Building (Orogeny) Configuration of Continents

29. Convection In The Earth

31. Plate Tectonics

33. The Carbonate-Silicate Cycle

34. Configuration of Continents Oceanic Circulation Weather and Climate Patterns –Deserts –Mountains and Rain Shadows Pathways for Migration Ecological Niches

35. Configuration of Continents