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2. Explore: Natural gas is a mixture of methane (CH4), ethane (C2H6), and other gases. Find two ways that natural gas forms. List the steps of the two carbon pathways below:
Path 1: Atmospheric CO2àLand plantsàsoilàAtmospheric CH4Path 2: Atmospheric CO2àLand plantsàLand animalsàAtmospheric CH4How is the formation of natural gas related to the formation of coal and petroleum? 3. Describe: Fossil fuels are used in many ways. Using the Gizmo, describe the main use for each fuel. In each case, what is the end product of burning the fossil fuel, and where does it go? Atmospheric CO2(Activity B continued on next page)
Activity B (continued from previous page)4. Explore: Another major contribution to atmospheric carbon dioxide is the cement industry. Using the Gizmo, find a carbon atom path from the atmosphere to the cement plant. (Hint: One of the ingredients in cement is limestone.) How is carbon dioxide produced in a cement plant? 5. Analyze: Click Reset, then navigate to the Land animals4. How do land animals create methane? A. Humans raise large numbers of cattle for food. How will these herds of cows affect Earth’s atmosphere? 6. Analyze: In many tropical rainforests, people clear land by cutting down trees and burning them. After a few years, the soil runs out of nutrients and cannot be farmed any longer. How does this practice of “slash and burn agriculture” affect Earth’s atmosphere? 7. Draw conclusions: In general, how do many human activities influence the carbon cycle? Scroll down the file to complete Activity C
Activity C: Modeling the carbon cycle Get the Gizmo ready: •Select the MODELtab. Introduction:Humans have been burning fossil fuels rapidly for the past 250 years. As a result, the amount of atmospheric CO2has increased by about 40% since the year 1800. By measuring how much carbon moves into and out of the atmosphere, scientists can predict the change in the amount of atmospheric carbon dioxide every year. Question: How can we model changes in atmospheric carbon over time? 1. Observe: The MODEL tab of the Gizmo shows a greatly simplified model of the carbon cycle. The ovals represent carbon reservoirs, where carbon is stored. The arrows represent the movement of carbon from one reservoir to another. A. What are the two major sources of atmospheric carbon?