1 Today Wednesday 21AUG13 Complete Unit 1 Section 4 Reading Guide If you have not taken Section 1 or 2 Quiz, you will today. PowerPoint Section 4 Quiz Section 3 tomorrow, Thursday.

2 Learning Targets: I can describe transitions the Earth has gone through and scientific reasons why. I can explain evidence from the deep past that is used to inform us about today’s conditions on Earth. I can explain how the Earth’s geological carbon cycle acts as a thermostat.

Unit 1 Section 4 Carbon Cycling and Earth’s Climate  Carbon Cycling and Earth’s Climate 3

34. Put the following in order (1,2,3,4) starting with what happened first. __4__ oceans were created __2__ planet’s surface cooled and solidified __1__ the rain of meteors and rock bodies from space ended from space ended __3__ water vapor in the atmosphere condensed and fell as rain condensed and fell as rain 4

35.Match the following terms to correct phase that describes each. Atmosphere water bodies Hydrosphere the solid part of the Earth Lithosphere layer of gases around the Earth 5

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36.The Earth’s geochemical cycle is the flow of chemical substances between: Atmosphere Hydrosphere lithosphere a. Atmosphere b. Hydrosphere c. lithosphere 7

a process that removes excess carbon from the atmosphere 37. During the development of the Earth’s atmosphere, the temperatures remained within a moderate range because the carbon cycle includes a natural sink - a process that removes excess carbon from the atmosphere

38. The carbon cycle has 4 basic stages. Describe each stage. 1. rainfall scrubs CO 2 out of the air, producing carbonic acid (H 2 CO 3 ), a weak acid. 2. this solution reacts on contact with silicate rocks to release calcium and other cations and leave behind carbonate and bicarbonate ions dissolved in the water. 3.This solution is washed into the oceans by rivers, and then calcium carbonate (CaCO 3 ), also known as limestone, is precipitated in sediments. Over long time scales, oceanic crust containing limestone sediments is forced downward into Earth's mantle. 4.Eventually, the limestone heats up and turns the limestone back into CO 2, which travels back up to the surface with magma. Volcanic activity then returns CO 2 to the atmosphere. 9

CO 2 outgassing from volcanoesCO 2 conversion to calcium carbonate through silicate weathering 39. This balance between CO 2 outgassing from volcanoes and CO 2 conversion to calcium carbonate through silicate weathering has kept the Earth's climate stable through most of its history

40. Why is Venus a runaway greenhouse while the Earth has fluctuated but has adjusted? 11 Venus has no water on its surface, so it has no medium to dissolve CO 2, form carbonic acid, and react with silicate rocks. As a result volcanism on Venus continues to emit CO 2 without any carbon sink, so it accumulates in the atmosphere.

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