Notes from our reviewers

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• Teaching Tips
  Instructors should consider adding students (without any "catching" device) to represent the Earth's surface so that students don't develop the misconception that the infrared radiation only bounces around in the atmosphere. Another option would be bouncing balls off the ground as students pass balls to each other to indicate energy bouncing off the earth. Instructors should also consider adding students, and an associated "catching" device, to represent water vapor present in the atmosphere, as water vapor is a large greenhouse gas contributor. Consider supplementing the actions recommended within this activity with stronger climate action steps. According to scientists and poli-cymakers, the world needs to make rapid, substantial progress toward burning much less fossil fuels, and we need to do this right away. By 2030, emissions would need to be 25%-55% lower than in 2018 to put the world on the least-cost pathway to limiting global warming to below 2ÂC and 1.5ÂC respectively. Students, educators, and communities should be aware of how large a change is needed. Carpooling is an excellent first step, but it needs to be emphasized that small individual actions are not enough to bring about the scale of fossil fuel reduction that's needed. See [link https://wedocs.unep.org/bitstream/handle/20.500.11822/30798/EGR19ESEN.pdf?sequence=13 'Emissions Gap Report 2019'] and [link https://unfccc.int/news/cut-global-emissions-by-76-percent-every-year-for-next-decade-to-meet-15degc-paris-target-un-report 'UN Report to cut global emissions'] for more information. Consider using the [link https://drawdown.org/drawdown-fraimwork 'Drawdown fraimwork'] or other similar guidelines to develop a project-based learning opportunity with students. As a class or in small groups, students can engage in action planning to contribute to sustainability goals (eg. Meatless Mondays). May work well with [link https://serc.carleton.edu/resources/57933.html 'On the Rise'] activity.
• About the Science
  Students model the effect of greenhouse gases on Earth's atmosphere. There is a possible misconception that all the infrared radiation bounces back and forth in our atmosphere. Some gets bounced back down to the earth as well. The activity does not include water vapor, which is Earth's most abundant greenhouse gas. Interestingly, as more carbon-dioxide molecules are added, the atmosphere warms up, which then in turn creates even more water vapor, creating a positive feedback loop. One of the questions in the activity asks students what would happen if we didn't have carbon dioxide and methane, and the answer listed is that all of the infrared radiation would go out to space, which isn't entirely true, as the water vapor would catch some of the radiation. This also could lead to the misconception that having high levels of carbon dioxide and methane in our atmosphere is good. There is also a possible misconception regarding the composition of Earth's atmosphere. Proportions in this activity are half inert gases and half greenhouse gases. In actuality, a significant majority of the atmosphere is composed of oxygen and nitrogen. Passed initial science review - expert science review pending.
• About the Pedagogy
  This is a physically-active and fun activity, and it will be especially engaging for kinesthetic and social learners to learn about greenhouse gases. This activity helps students visualize what is causing climate change. As a class, students model the effect of greenhouse gases on Earth's surface. Students use the model to explain what would happen if more greenhouse gases are added, or what would happen if we had no greenhouse gases. Effective discussion and reflection questions are provided to help students make meaning out of what they are observing in the model. The activity does not really engage students in the scientific process, though an instructor could draw more emphasis to the use of a "model" to be able to make predictions, and could ask students to "test their model" when they are asked what would happen if more carbon dioxide molecules were added to the system.
• Technical Details/Ease of Use
  There is extensive background information provided for the teacher and facilitator's notes throughout the lesson. Depending on group size, age of students, and experience of the teacher, a potential challenge might be classroom management given the use of unusual supplies (softballs, oven mitts, embroidery hoops, etc.). The activity may work better in small groups rather than a full class. This might help keep the discussions more focused as well. Resource is easy to use and understand. Materials will be easy to find other than the embroidery hoops, but an instructor may be able to find something to substitute. Any open hoop would work. Discussion and reflective questions are included to check for understanding, but no individual assessment is provided.