This activity is part of the Climate Change Challenge unit.
 
1. Facilitate the design of an initial conceptual model of the greenhouse effect using a reading.

• Distribute the leveled article Greenhouse Effect. Assign students to read and annotate the first section of the article individually, highlighting or circling the following terms:
• Greenhouse gases
• Atmosphere
• Sunlight (sun’s light)
• Earth’s surface
• Heat
• Have students Think-Pair-Share to assess the role each of these terms plays in the greenhouse effect.
• Distribute the Our Greenhouse Models worksheet to students, and prompt students to use the reading and their notes to complete Part A. Their visual, conceptual model should contain each of the terms discussed previously, with these elements and their relationships clearly labeled.
• Connect students’ models and initial ideas from the reading to the conclusions of the Heating Up activity, and explain that today they will collect their own data and use models to explain the processes responsible for global warming.

 
2. Demonstrate the greenhouse effect using a physical model and have students record and analyze resulting data.          

• Introduce students to a physical model of the greenhouse effect.
• See the Setup section for instructions on how to create this model prior to class.  
• Clearly emphasize the presence of carbon dioxide in the atmosphere within one bottle and its absence in the other.
• Have students Think-Pair-Share to relate this physical model to their visual, conceptual model with the following questions: 
• How do the pieces of this model (lamp, bottles, bubbles, water, temperature) relate to your model of the greenhouse effect? (The lamp models sunlight, the bottles model the atmosphere. The bubbles are made of carbon dioxide. Water models the Earth’s surface, and temperature measures the heat produced.)
• What is your hypothesis for how the temperature will compare between     these two bottles after we measure them for 20 minutes? (Student hypotheses may vary, but should include a statement regarding the relative temperature in the two bottles, and a justification using prior knowledge.)
• Turn students’ attention to Part B of Our Greenhouse Models. Ask students to record temperatures in each bottle every 15 minutes until all three readings are taken.
• Use the intervening times to introduce the definitions of mean, median, and range, and practice calculating each.
• If students have prior knowledge of the terms mean, median, and range, solicit student definitions of these terms. Otherwise, introduce them, encouraging students to record definitions in their own words for their notes.
• Mean (Also known as the average. Mean is calculated by adding a group of observations, and then dividing by the number of observations in the data).
• Median (This is the "middle" number in a set of observations put in order from smallest to largest. If there are an even number of observations, the median is the mean of the middle two.)
• Range (The difference between the smallest and largest value in a set of numbers. It gives a sense of the amount of variation in the dataset.)
• Model calculating mean, median, and range with hypothetical temperature data, in an I do, we do, you do format. For example: 68, 64, 68 (Rewrite numbers in order (64, 68, 68) and then calculate Mean: (64+68+68)/3 = 65.33; Median: 68; Range: 68-64 = 4.)
• Calculate mean, median, and range for the greenhouse effect data (extra carbon dioxide/seltzer) and the no greenhouse effect data (air/water). Discuss these statistics with the class by asking:
• How did these data change over time, from Reading 1 to Reading 3? Why?
• (Readings for both bottles likely increase with time, because the lamp heats the "atmosphere" inside the bottles.)
• Which mean/median/range is higher? Why?
• (Mean and median for the greenhouse effect bottle will be higher, if the model has run for an extended period of time, such as 20 minutes. This is because the greenhouse gas carbon dioxide is helping the atmosphere inside that bottle trap more heat. Range may or may not be different for the two.)
• Was your temperature comparison hypothesis from before the experiment correct?
• (Students' responses will vary, but look for novel incorporation of information related to the greenhouse effect as students revise their understanding.)

3. Use an interactive to help students revise conceptual models of the greenhouse effect.

• Introduce students to the Carbon Dioxide in the Atmosphere online interactive by projecting it, explaining that this tool will help them to build on their growing knowledge of the greenhouse effect. Use the following elements to demonstrate how releasing more carbon dioxide causes an increase in temperature and track an energy packet through the environment:
• The Key (identifies carbon dioxide, heat, and solar radiation – sunlight). Click “Show Key” in the top left-hand corner of the interactive.
• The Play button (necessary to start the interactive).
• The Erupt button (necessary to release carbon dioxide into the atmosphere).
• The Slow-Fast switch (slowing the interactive down is necessary to see the details of the greenhouse effect).
• The Follow energy packet and Follow CO₂ buttons (using these will make it much easier to see the details of the greenhouse effect).
• The graphs (air temperature and CO₂ graphs help students relate these two model components).
• Based on this model, assign students to revise their model of the greenhouse effect in Part C of the Our Greenhouse Models handout. Prompt students to incorporate the terms greenhouse gases, atmosphere, sun’s light (sunlight), Earth’s surface, and heat and their relationships, and using symbols such as arrows accompanied by + or - to show how one element might influence another. Regardless of the accuracy of their initial model, students can illustrate this effect again in a novel way.
• Ask for volunteers to share their revised models with the class, and use information from these models to update the class unit Know and Need to Know chart regarding the greenhouse effect.  
• Prompt all students to complete Part D of the Our Greenhouse Models handout explaining what they learned from data collection and the interactive that helped them revise their model, as a reflection on their learning in this activity.
• Specifically, students might name general conclusions from data collection (the bottle with carbon dioxide heats more quickly under light than the bottle with air) or particular actions of the model elements (greenhouse gases, atmosphere, sunlight, heat, and Earth’s surface) that they witnessed in the interactive.