20 Lesson Plan: Climate Change Greenhouses Gases July 19, 2011

Transcription

1 Background: Climate Change Climate change is a pressing issue in today s society. If we as a population want to be able to make important decisions regarding climate change and global warming we must begin teaching our kids about the issues. It is only by their understanding of this topic that we will be able to come to a consensus on what to do in the future. This understanding must start at a basic level and build up until the students have a thorough understanding of the processes involved in this complicated system we call Earth. When starting to discuss the overall issue of climate change with students it appears to be best to begin by discussing the carbon cycle and the greenhouse effect. In an article written by Shepardson, Niyogi, et. al., they reference students understanding of the carbon cycle and its connection to the greenhouse effect as the foundation from which students build a conception of global warming (Shepardson, Niyogi, Choi, & Charusombat, 2009). The carbon cycle must be explained before students can begin to understand how carbon dioxide is put into the atmosphere. Once the concept of carbon dioxide and other greenhouse gases in the atmosphere is discussed it opens up the discussion about the Greenhouse Effect. Scientific Understanding The Earth has an energy budget which is used to describe the balancing of incoming and outgoing energy. Incoming energy is mostly in the form of visible light and ultraviolet radiation. The outgoing energy is mostly in the form of heat radiation. Some incoming solar radiation is absorbed by the surface, clouds and atmosphere while some is reflected. The energy that is absorbed may be reflected or can be re-radiated back as longwave radiation in the form of heat. This is what warms the Earth. Heat energy is absorbed by the atmosphere and dispersed greenhouse gases and radiated back to the surface this in a process that is known as the greenhouse effect. Variations in our global temperature can be attributed to variations in the amount of incoming solar energy, variations in the amount of reflected solar energy or variations in the amount of heat trapped near Earth s surface (Smith, & Pun, 2010). 1

2 Misconceptions Common misconceptions about the topic of the greenhouse effect involve greenhouse gases. Many students are unaware that there are many types of greenhouse gases. They are often only familiar with carbon dioxide as a greenhouse gas. In a study done by Shepardson, Niyogi, Choi and Charusombat (2009) 84% of seventh graders interviewed referred to greenhouse gas, but did not identify a specific gas (Shepardson, Niyogi, Choi, & Charusombat, 2009). Another misconception commonly held is that greenhouse gases, including carbon dioxide, are found in a condensed layer in the atmosphere. When asked to draw a representation of the greenhouse effect, several students drew a relatively thin layer of greenhouse gases above the surface of the Earth. Even among the 13% of students who had a more developed concept of the greenhouse effect, half of them drew carbon dioxide as a layer in the atmosphere (Shepardson, Niyogi, Choi, & Charusombat, 2009). 2

3 Example Lesson Plan I. Subject/Topic/Grade This lesson will introduce the concept of the greenhouse effect and greenhouse gases. It will also explore the configuration of greenhouse gases in the atmosphere as dispersed rather than in a layer. It is designed to be taught to middle school students. II. Context This lesson is appropriate for students in grades 6 to 8 as part of a unit on climate change. Students should have previous knowledge of the carbon cycle. III. Specific Learning Objectives A specific learning objective for this lesson is: E.FE Describe the atmosphere as a mixture of gases. (Michigan Department of Education). IV. Strategies and Activities Day One Pose the following questions: What are greenhouse gases? Can you name any greenhouse gases? What is the greenhouse effect? Explain to students that they will be doing a research paper about the greenhouse effect. Students should be given a list of articles and websites that are reliable sources of information. The research paper will be about the greenhouse effect and greenhouse gases. Students will be given the rest of the class period to start their research. Homework should be given to find and describe greenhouse gases. Day Two Students should have a discussion about what they have found in their research in relation to greenhouse gases. Students will do an experiment about greenhouse gases, specifically carbon dioxide and water vapor. Divide the class into three groups. Each group will explore a different gas with one group being a control 3

4 group. Students will tape one thermometer to the bottom of the inside of the tank and another thermometer somewhere near the top of the tank. In the bottom of two of the tanks there should be a small dish. One dish will hold baking soda, the other will hold a small amount of water. Vinegar should be mixed with the baking soda to create carbon dioxide. Lids should be placed on the tanks. Place the heat lamps directly above the fish tanks and turn them on. Students should record the temperature on both thermometers at set intervals. While they are waiting to record data, ask students if greenhouse gases are found in layers. If this is true, will the temperatures be the same on both thermometers or will only one thermometer record a temperature change? Discuss the results as a class and confirm that greenhouse gases are dispersed throughout the atmosphere. VI. Materials Three fish tanks Six thermometers Two small dishes Tape Baking soda Vinegar Water Three heat lamps References Shepardson, D.P., Niyogi, D., Choi, S., & Charusombat, U. (2009). Seventh grade students' conceptions of global warming and climate change. Environmental Education Research, 15(5), Smith, G.A., & Pun, A.. (2010). How does earth work?: physical geology and the process of science. Upper Saddle River, NJ: Pearson Prentice Hall. 4

5 5