Energy

1. Energy Non-renewable and Renewable Resources

2. The Earth’s Interior • Composed of 4 layers • Crust • Mantle • Outer Core • Inner Core

3. Crust • Temperature: Over 175 degrees Celsius • Topmost layer of the Earth • Relatively cool • Made of rock • 2 types of crust • Oceanic (4-7 km thick) • Continental (20-40 km thick)

4. Mantle • Temperature: Over 1250 degrees Celsius • Makes up about 80% of the Earth’s volume • ~ 2900 km thick • Outer mantle – rocks • Inner mantle – “plastic”

5. Core • Temperature: Over 6000 degrees Celsius • Outer core – liquid • Pressure from the mantle & crust do not allow the metals in the outer core to become gasses • Inner core – solid • Pressure from the mantle and crust do not allow the metals to become liquid

6. Plate Tectonics • The Earth’s lithosphere is made up of 7 tectonic plates • Plate tectonics – the movement of these lithospheric plates

8. Why do the plates move? • One theory suggests that plates move due to the convection currents in the asthenosphere (“plastic” inner portion of the mantle)

9. Divergent Plate Boundaries • 2 plates move apart • Magma fills the gap created from this movement • Magma cools as it reaches the Earth’s surface creating rift valleys

11. Convergent Plate Boundaries • Oceanic plates dive beneath continental or oceanic plates (called subduction) • Creates deep ocean trenches

12. Wall diving- coral reefs form over time on the “walls” of deep sea trenches. Many are thousands of feet deep.

13. Convergent Plate Boundaries • Mountains form at the convergent plate boundaries as magma from the mantle rises, pushing continental crust upward

14. Convergent Plate Boundaries • Volcanoes form at the convergent plate boundaries as magma rises to the surface and cools

15. Transform Fault Boundaries • Plates move past each other at cracks in the lithosphere (called faults) • Transform fault boundary – horizontal movement between two plates

16. Earthquakes • Occur at plate boundaries • Plates slide past each other creating pressure • Rocks break along the fault line • Energy is released, called seismic waves

17. San Andreas Fault

18. Focus = point of earthquake origination Epicenter = point on the Earth’s surface directly above the focus

19. Energy from an earthquake • Energy is released in the forms of waves • P wave: Primary or longitudinal waves originate from the focus & move quickly through rock. These are the first waves to be recorded • S wave: Secondary or transverse waves originate from the focus & moves more slowly through rock. • Surface waves: move across the earth’s surface, causes building to collapse

20. Earthquake Measurement • Seismograph • Records data about P, S and surface waves • Used to locate the epicenter of an earthquake • Richter scale • Measures energy released at the epicenter of an earthquake (in magnitude) • Each step up in magnitude represents a 30-fold increase in energy released!

22. Volcanoes • Volcanoes result from openings or vents in the Earth’s surface • Magma reaches the surface through these vents • When magma reaches the surface it changes physically and is called lava

23. Shield Volcano • Formed from fluid lava, rich in iron • Shield volcanoes are large Mauna Loa in Hawaii

24. Composite Volcano • Made of alternating layers of lava, ash and cinders. • Magma is rich in silica and thick • Large with steep slopes

25. Cinder Cone • Large amounts of gas are trapped in the magma causing violent eruptions • Active for short periods of time

26. Minerals & Rocks • Minerals: • naturally occurring, inorganic substances • (inorganic = does not contain Carbon) • can be expressed by a chemical formula • Quartz SiO2 (silicon dioxide) • Rocks: • Composed of minerals

27. Types of Rock • Igneous • Formed when magma or lava cools and hardens • Magma forms intrusive igneous rock • Lava forms extrusive igneous rock • Sedimentary • Formed when rock particles, plant and animal debris are carried away by water, redeposited, then fused together • Metamorphic • Rock particles are fused together by pressure beneath the Earth’s surface

28. Determining the age of rocks Two ways to “determine” the age of a rock: • Superposition – determine the age based on layers, older rocks are on the bottom, newer ones on top • Radioactive dating

29. The Rock Cycle

30. Weathering and Erosion • Two types of weathering • Physical • Breaks rocks into smaller pieces, chemical composition does not change • May be caused by ice or plants • Chemical • Changes the chemical composition of rocks • May be caused by oxidation or acid rain

31. Erosion • Erosion: the process of loosening and removing sediment • Caused by water, glaciers, wind

32. Deposition • Occurs when loose sediment is laid down • Causes river beds to widen and deltas to form.

33. Important Elements • Oxygen – most abundant element in the Earth’s crust • Nitrogen – most abundant element in the atmosphere • Iron – most abundant element in the core

34. Non-renewable Resources • Defined: • An energy source that cannot be renewed in our lifetime • Examples: • Oil • Natural Gas • Coal • Aluminum • Gold • Uranium

35. Non-renewable resources – Environmental Impacts • Mining • IMPACTS: • Disrupts land • Disrupts ecosystems • Causes acid rain

36. Surface Mining • Description – if resource is <200 ft. from the surface, the topsoil is removed (and saved), explosives are used to break up the rocks and to remove the resource, reclamation follows • Benefits – cheap, easy, efficient • Costs – tears up the land (temporarily), byproducts produce an acid that can accumulate in rivers and lakes

37. Underground Mining • Underground Mining • Description – digging a shaft down to the resource, using machinery (and people) to tear off and remove the resource • Benefits – can get to resources far underground • Costs – more expensive, more time-consuming, more dangerous– mining accident in Chile

38. Coal • formed from ancient peat bogs (swamps) that were under pressure as they were covered. • Used for electricity, heat, steel, exports, and industry, may contribute to the “Greenhouse Effect” • Four types of coal exist: lignite (soft, used for electricity), bituminous and subbituminous (harder, also used for electricity) and anthracite (hardest, used for heating) • 50% of all the coal is in the United States, the former Soviet Union and China

39. Increasing heat and carbon content Increasing moisture content Peat (not a coal) Lignite (brown coal) Bituminous (soft coal) Anthracite (hard coal) Heat Heat Heat Pressure Pressure Pressure Partially decayed plant matter in swamps and bogs; low heat content Low heat content; low sulfur content; limited supplies in most areas Extensively used as a fuel because of its high heat content and large supplies; normally has a high sulfur content Highly desirable fuel because of its high heat content and low sulfur content; supplies are limited in most areas Fig. 16-12, p. 368

40. Waste heat Cooling tower transfers waste heat to atmosphere Coal bunker Turbine Generator Cooling loop Stack Pulverizing mill Condenser Filter Boiler Toxic ash disposal Fig. 16-13, p. 369

41. COAL • Coal reserves in the United States, Russia, and China could last hundreds to over a thousand years. • The U.S. has 27% of the world’s proven coal reserves, followed by Russia (17%), and China (13%). • In 2005, China and the U.S. accounted for 53% of the global coal consumption.

42. Reclamation • returning the rock layer and the topsoil to a surface mine, fertilizing and planting it • Benefits – restores land to good condition • Costs – expensive, time-consuming • In the United States, mining companies are required to do this!

43. Open-pit Mining • Machines dig holes and remove ores, sand, gravel, and stone. • Toxic groundwater can accumulate at the bottom. Figure 15-11

44. Area Strip Mining • Earth movers strips away overburden, and giant shovels removes mineral deposit. • Often leaves highly erodible hills of rubble called spoil banks. Figure 15-12

45. Contour Strip Mining • Used on hilly or mountainous terrain. • Unless the land is restored, a wall of dirt is left in front of a highly erodible bank called a highwall. Figure 15-13

46. Mountaintop Removal • Machinery removes the tops of mountains to expose coal. • The resulting waste rock and dirt are dumped into the streams and valleys below. Figure 15-14

48. United States mining • Central – diamonds (Arkansas), bituminous coal • West – bituminous and subbituminous coal, gold, silver, copper • East – anthracite coal, bituminous coal • South – some gold (SC), bituminous coal • North – bituminous coal, some gold (SD, WI)

49. Energy from non-renewable resources • Cogeneration • Primary • Secondary

50. Fossil Fuels • Only about 30% efficient • Benefits – • easy to use, currently abundant • Costs – • a nonrenewable resource, produces pollutants that contribute to acid rain and the greenhouse effect • Oil- Supplies the most commercial energy in the world today. People in the U.S. use 23 barrels of petroleum per person or 6 billion barrels total each year!!!