This unit will take place over six 80-minute periods, covering the following topics:
Lesson 1 - Modeling the carbon cycle
Students will be able to:
- Describe the reservoirs where carbon is stored
- Describe how carbon moves between the reservoirs in the pre-anthropogenic carbon cycle
- Determine how plants and animals convert carbon from one form to another
Students will first learn about the reservoirs where carbon is stored (land, ocean, atmosphere, sedimentary rock. They will then model how carbon moves through the carbon cycle by playing the carbon cycle game. In the first version of this game, fossil fuels will be left out. After playing 10 rounds of the game, students will reflect on where the carbon molecules spent the most time and how quickly they were able to move from one reservoir to another. Students will also conduct a mini-lab in which they will determine whether plants and animals produce carbon dioxide. They will first perform a control test in which they mix baking soda and vinegar and observe the color change of bromothymol blue when exposed to the carbon dioxide gas. They will then determine whether animals produce carbon dioxide by blowing through a straw into a solution with bromothymol blue. The color change will indicate that carbon dioxide is produced. For a third test, students will place a sprig of elodea into a covered test tube with bromothymol blue, and observe if there is a color change after 24 hours.
Lesson 2 - Human impact on the carbon cycle
Students will be able to:
- Identify 6 greenhouse gases
- Explain how fossil fuels produce carbon dioxide
- Create a model of the anthropogenic carbon cycle
During this lesson, students will use the Greenhouse Gas Cards10 to learn about the 6 main greenhouse gases (carbon dioxide, water vapor, methane, ozone, and chlorofluorocarbon). Students will then play the carbon cycle game again, adding in the fossil fuels station. They will then reflect on how the fossil fuels change the way that carbon moves through the cycle. Finally, students will create a model of the carbon cycle based on what they learned in lesson 1 and 2. Their model can include pictures and/or descriptions to show how carbon flows through the different reservoirs in the anthropogenic era. As a homework assignment, students will use an online carbon footprint calculator to determine how much carbon they produce in their daily life in order to make this concept more relevant.
Day 3 - Analyzing graphs
Students will be able to:
- Analyze a graph of carbon dioxide and temperature emissions over time
- Determine patterns in temperature and carbon dioxide data
- Write a claim, evidence, reasoning paragraph that describes how industrialization has increased carbon dioxide levels
To begin this lesson, students will observe one graph that shows temperature vs time and one graph that shows carbon dioxide levels vs time over the last 300 years. Students will write down three things that they notice from these graphs and three things that they wonder. They will then discuss their observations and questions in small groups. Next, students will examine graphs that show carbon dioxide levels over the last 100, 500, and 800,000 years through looking at data from the ice cores. Based on these graphs, students will write a claim as to how industrialization has affected the amount of carbon dioxide in the atmosphere.
Day 4- Lab - how does carbon dioxide affect the temperature of the atmosphere
Students will be able to:
- Collect data to measure temperature over time
- Create a graph of temperature vs. time for three different scenarios
- Write a claim for how the presence of carbon dioxide affects the temperature
Students will conduct an experiment that models how carbon dioxide acts as a greenhouse gas and increases the temperature of earth. Students will set up three bottles, equidistant from a heat lamp. In one bottle, they will add a given amount of water and leave the top open. In a second bottle, they will close the top of the bottle. In the third bottle, they will add alka seltzer in order to release carbon dioxide into the bottle. They will then measure the temperature of each of the bottles every 5 minutes for a 60 minute lab period. At the end of the lab, they will create graphs of temperature vs. time for each of the three bottles and analyze the graphs to determine how the presence of carbon dioxide affects the temperature in the bottle.
Day 5 - Climate sensitivity
Students will be able to:
- Use a model to predict how increasing carbon dioxide will affect the global temperature
- Explain the benefits and challenges of climate models
To begin this lesson, students will use the EN-ROADS climate change simulator (https://en-roads.climateinteractive.org/scenario.html?v=21.6.0) to examine how various factors affect the temperature. Using the “Net CO2 Emissions”, they will first observe the predicted temperature increase under current conditions. They will then choose at least three different factors to change and examine how those factors affect the predicted temperature increase. Next, students will watch Kate Marvel’s Ted Talk: https://www.ted.com/talks/kate_marvel_can_clouds_buy_us_more_time_to_solve_climate_change. This Ted Talk introduces the idea of climate models and explains some of the challenges that models face in predicting how the temperature will change in the future. The video specifically focuses on clouds, discussing how clouds both increase and decrease the temperature. Finally, students will read a short article on climate sensitivity11, which will explain what climate sensitivity is and how different models contribute to the estimate of temperature change.
Day 6 - Creating a model
Students will be able to:
- Create a model of how carbon dioxide contributes to climate change
- Make a recommendation to reduce climate change based off of the role of carbon dioxide in rising temperature
As a concluding project, students will develop their own models of the role that carbon dioxide plays in climate change. Using what they have learned about the carbon cycle, the effect of fossil fuels on the carbon cycle, and the various models of climate sensitivity, students will be able to design a model and make a prediction as to how they think the levels of carbon dioxide will continue to change and how that will affect the temperature. As a final extension, students can make a recommendation for how to reduce climate change and describe how that change will affect their model.