Review terms: fossil fuels, climate change, and air pollution, greenhouse effect.
Ask students what they think happens when fossil fuels are burned. Turn and talk. Many students know that burning anything will lead to air pollution, so use this as an opportunity to introduce the concept of greenhouse gasses.
Watch NASA greenhouse gas video.
Ask students to turn and talk to describe their new knowledge about what happens when fossil fuels are burned. (formative)
Explain that a model is something that represents an object or process, typically on a smaller scale. In this model, we are representing what happens during the greenhouse effect on our planet by using a smaller model with visible results to help us understand this process.
Introduce the model. Beaker 1 will represent the Earth without the additional greenhouse gasses. Beaker 2 will represent the Earth with extra carbon dioxide forming an added barrier, keeping more heat in. The Alka-Seltzer tablets will form CO2 gas as they dissolve in the water.
Make a prediction: Students should record what they predict will happen to the temperature in the beaker without the Alka Seltzer and the beaker with the Alka Seltzer in their science journals (cause and effect).
- Distribute the greenhouse effect data sheets (options: display data sheet on Smart Board and ask students to copy into their science notebook or upload document to Google Classroom and allow students to complete.
- Use the modeling clay to attach a thermometer to each beaker. It should be angled with the tip inside but not touching the edge. Make sure each thermometer is the same distance in, approximately 5cm from the beaker edge to the tip of the thermometer is a good distance.
- Add 200mL of water to each of the beakers.
- Prepare your lamps. Set them up next to each other with the necks angled so they will just fit over the tops of the beakers. Turn them on so they are ready.
- Have students record the starting temperature – it should be the same in both beakers.
- Add both Alka-Seltzer tablets to one of the beakers (beaker 2), and immediately cover both beakers with cling wrap. A tight seal around the edge will work best, and make sure thermometers are left visible so you can record the temperature.
- Slide each beaker under one lamp and turn it so the thermometer is visible.
- Record the temperature in both beakers every 5 minutes for 30 minutes or until the temperatures stabilize.
Students should take turns recording temperatures and making observations on their data recording sheet. (formative)
Review the questions at the bottom of the data sheet with the class: (Analyze and Interpret data) (formative)
- What is happening to the temperature in beaker 1? Why? What is happening to the temperature in beaker 2? Why?
- How is this similar to what is happening on Earth?
- What are two problems that are caused by global climate change? (cause and effect)
Discuss with the students:
- What are some of the problems associated with using fossil fuels for energy? (The problems/issues with this effect are more drought and more flooding, less ice and snow, more extreme weather incidents, rising sea level.)
- What are some human activities that contribute to the greenhouse effect? (burning fossil fuels, clearing of land)
- What are some things that we can do to lessen these problems in our world? (conserve energy, use more efficient technology that consumes less energy, encourage the use of renewable energy sources)
- What are some things students can do in their lives to use less fossil fuels? (unplug electronics, use less water, recycling, wear used clothing)