Summary

In this lab, students will create two simulations of the Earth’s atmosphere. They will compare a control model with a one that has an increased presence of carbon dioxide gas in order to analyze how this effects temperature. They will also complete research in order to learn more about the makeup of the Earth’s atmosphere.

Grade Level

Middle or high school

Objectives

By the end of this lab, students should be able to

• Identify the types and percentages of each gas that makes up the Earth’s atmosphere.
• Explain what events, both past and present that lead to an increase in carbon dioxide levels in the atmosphere.
• Analyze a simulation that compares two different models of the Earth’s atmosphere, and measure the temperatures of each.

Chemistry Topics

This lab supports students’ understanding of

• Gas
• Temperature
• Chemical Change
• Energy

Time

Teacher Preparation: 30 minutes

Lesson: 60 minutes

Materials

Per student group, students are in groups of 2 or 3

• 1 Tablet/Chromebook
• 3 tablets Alka-Seltzer
• 2 empty, clear 2-liter bottles
• 2 liters of Water
• 2 rubber stoppers with hole in the center that fit 2-liter bottle openings (use modeling clay if these are not available)
• 2 temperature sensors (use thermometers if these are not available)
• Heat lamp or 100 watt spotlight and bulb holder with clamp
• Timer

Safety

• Always wear safety goggles when handling chemicals in the lab.
• Students should wash their hands thoroughly before leaving the lab.
• When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.
• Exercise caution when using a heat source. The heat lamp should be turned off and unplugged as soon as it is no longer needed.
• When using the heat lamp make sure it is not too close to the 2-liter bottles and exercise caution while it is on.

Teacher Notes

• This lesson can be done as a demonstration or in small groups depending on the number of available temperature sensors or thermometers. The student directions are written as if each group is to carry out their own experiment.
• This lab is designed so that once it begins, students will periodically collect and graph the temperature data. In the meantime they will be using a tablet or Chromebook type device to be completing the research component.
• Students will research and discover that Alka-Seltzer tablets were used because when placed in water they cause a chemical reaction that produces carbon dioxide. This will cause an increase in carbon dioxide in one of the sealed 2-liter bottles which should register higher temperatures when placed near a strong light/heat source.
• Variations:
  • Students may be provided with a data table and double line graph instead of creating one on their own. This is dependent on if they have been previously taught how to create an appropriate data table and double line graph.
    
    
  • The 2-liter bottles could be replaced with any other container that traps the air but allows the radiant energy from the bulb to increase the thermal temperature inside the container.
    
    
  • Digital thermometers can be replaced with traditional thermometers provided they fit inside the container. All attempts should be made to monitor the air temperature near the top of the container though.
    
    
  • A heat lamp works best. A household bulb is likely not bright enough to produce measureable results.
    
    
  • Possibly use more than 2 bottles (control and experimental) and use multiple bottles with different quantities of Alka Seltzer tablets.
    
    
  • Consider spreading this lesson out as a STEM based unit in which students are given the task to create their own experiment to simulate greenhouse gas increases. Also, add 1 extra day at the end of the unit where students spend more time researching question #8 “In your opinion, what should be done by humans to protect Earth’s atmosphere?” Students can then present their findings through formal class discussions.