Lab Activity: Observing Greenhouse Gases

Please be sure to check out the video demonstration of this blog below!

This lab is suitable for high school students.

Objectives for this lab:

• Model the greenhouse effect.
• Graph and compare the effectiveness of different naturally occurring greenhouse gases.

Materials:

• 3 1-quart glass jars
• 3 Celsius thermometers (available at teaching supply stores such as A-Plus or science supply vendors such as Nasco or Delta).
  
• Masking tape
• Marker
• Oven mitts
• Lab apron
• Dry ice (you can often find this at the grocery store)
• Tongs
• Steam (boil some water to get steam)
• Colored pencils
• Graph paper

Background information: The glass windows of a greenhouse allow light and heat from the sun to enter but do not allow infrared radiation to leave. This trapped radiation causes the air in the greenhouse to heat up. The greenhouse effect gets its name because the gases in the Earth's atmosphere are like the windows of the greenhouse. They trap or absorb the infrared radiation from the sun rather than allowing it to escape into space. Some gases are able to absorb more radiation than others and the greenhouse gases are especially good at absorbing it. In this lab, you will have the opportunity to work with three different gases - water vapor, air, and carbon dioxide. In this lab you will compare these gases to find out which one is the most effective greenhouse gas.

**Safety Notes:

• You should always use dry ice in a well-ventilated area. Since this is a lab you will complete at home, it is a good idea to complete this lab outside.
• Wear your apron and have oven mitts ready. Do not handle dry ice with your bare hands.
  

Lab Procedure:

1. Use the masking tape and a marker to label the three jars with the following: Air, Carbon dioxide, and Water vapor.
2. Tape a thermometer to each jar lid so the thermometer's bulb hangs suspended in the jar.
3. Leave the jar labeled Air open for a few moments and then seal the jar.
4. Put on your apron and oven mitts. Wear oven mitts when handling the jars labeled Carbon dioxide and Water vapor.
5. Drop a piece of dry ice (remember, do not touch this with your bare hands) into the jar labeled Carbon dioxide. The dry ice will sublimate (change from a solid to a gas with no liquid phase in between). Once all the dry ice has sublimated, seal the jar.
6. Hold the jar labeled Water vapor upside down over boiling water. Once steam has filled the jar, seal the jar.
7. Once all the jars are sealed, use a copy of the data table shown below to record the starting temperature of each jar.
8. Move the jars into direct sunlight. Record the temperature of each jar every 5 minutes for the next 30 minutes.
9. Move the jars into shade, away from any heat sources, and record the temperature of each jar every 5 minutes for an additional 30 minutes.
10. Use graph paper to graph your results with "Time (minutes)" on the x-axis and "Temperature (C)" on the y-axis. Use a different colored pencil for each jar

Analysis and Conclusions:
Feel free to use the "Comments" section to post your answers to these questions.

1. Which jar heated up the most in the sunlight? Which jar heated up the least?
2. To calculate the rate of cooling, subtract the final temperature from the temperature recorded for each jar just before it was moved into the shade; then divide by the number of minutes the jar cooled (30). Calculate the rate of cooling for each jar. Which jar cooled most quickly? Least quickly? How do these compare with your answers to Question 1?
3. Imagine an ideal greenhouse gas. How would it behave in terms of maximum temperature and rate of cooling? From your answers to Questions 1 and 2, identify the most effective greenhouse gas among the gases you tested.
   
4. Brainstorm ways that humans affect the amount of each gas that you studied in the atmosphere. Try to identify human activities that contribute to the increase of these gases in the atmosphere.
5. Brainstorm ways humans can decrease the amount of the greenhouse gas you identified in Question 3 that is released into the atmosphere.
6. What other gases in the atmosphere can you think of that might influence the greenhouse effect? How common are these gases? How might you collect them in jars for experimentation?
7. Describe what you think Earth might be like if the greenhouse gas did not exist. Describe what you think the Earth would be like if the greenhouse effect were much greater than it is today. Explain your answers.

Visit this website to learn more about greenhouse gases: ClassZone.

Reference:
Spaulding, N.E. and Namowitz, S.N. (2005). Earth Science. Evanston, IL: McDougal Littell.

Video Part 1:



Video Part 2:




Thank you! A huge thank you to my husband for playing "director" and video-taping this lab for us.