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Earth Systems Science Core
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On a global scale carbon dioxide, water vapor and other gases present in the atmosphere are similar to the glass in a greenhouse. Ultraviolet radiation from the sun, having a short wavelength, can pass through the glass. Once inside the greenhouse, the ultraviolet radiation is absorbed by soils, plants and other objects. Upon absorption it becomes infrared radiation, or heat energy having a shorter wavelength. Because of this, infrared radiation cannot escape through the windows, which act like a large blanket that reradiate the infrared energy back into the greenhouse. This phenomenon naturally causes the overall temperature within the greenhouse to increase. See Figure 1.
 
The same gases that create a warming greenhouse effect can also create a cooling effect. How is this possible? Refer again to Figure 1. Much of the ultraviolet energy from the sun also gets scattered, absorbed and reflected by carbon dioxide, water vapor, volcanic dust, methane and solid particulates and aerosols created by humans. The solar energy that is reflected does not pass through the troposphere and does not allow for heat generation upon striking Earth's surface. This causes a cooling effect. An increase in carbon dioxide and other greenhouse gases eventually can create a cooling effect which could possibly alter weather and climates.
 
 
During this investigation you will create a model demonstrating the greenhouse effect. The experiment involves creating a greenhouse environment of carbon dioxide within a container. The investigation provides evidence that carbon dioxide can prevent or slow heat energy from entering an experimental container. You will measure temperature variations caused by the carbon dioxide atmosphere at the surface of the container and inside the container for data.
 

Materials:

  • Empty fish aquarium or a large beaker or flask
  • Dry ice
  • Gloves or tongs
  • Safety glasses
  • Heat lamp
  • Two thermometers (Celsius or Fahrenheit)
  • Styrofoam cup of water
 
Safety concerns: Be sure to keep all chemical, electrical, eye, heat, and glassware safety rules. Handle the dry ice only while wearing gloves or using the tongs. Do not place the dry ice in a closed container. As with all science lab activities, the most important safety rule is to follow all teacher directions.
 

Procedure:

  1. Allow both thermometers to acclimate to room temperature.
  2. Tape one thermometer to the top of the container.
  3. Tape the second thermometer inside the container, near the bottom.
  4. Place a heat lamp over the container.
  5. Turn on the heat lamp.
  6. After three minutes record the temperature of both thermometers.
  7. Keep the heat lamp on and place a chunk of dry ice into the cup of water and place the cup into the aquarium.
  8. Allow the CO2 vapor to fill the container.
    • While this is happening observe the temperature readings of the outside thermometer and the inside thermometer if you can see it.
  9. When the CO2vapor begins to subside, record the temperature of both thermometers and compare them.
  10. Leave the heat lamp on and allow all the CO2 to leave the container.
  11. Three minutes later, record the temperature of the two thermometers.
  12. Make observations and conclusions about this experiment.
 
 

Analysis:

  1. Which of the two thermometers had the highest reading after the carbon dioxide had filled the container? Answer
  2. What happened to the temperature inside of the container as the carbon dioxide filled the container? Answer
  3. If greenhouse gases become too thick in Earth's atmosphere, describe two major effects that they can have on Earth. Answer
  4. Besides carbon dioxide and water vapor, other greenhouse gases and particles that can decrease Earth's air temperature include methane, aerosols and solid particulates. What are some natural and manmade processes that produce these? Answer
 

Extension:

Conduct the suggested activity of this unit again, this time using some temperature probes and Texas Instrument CBL® or a LAB PRO® by Vernier. Follow the same procedure you used for this unit.

 
Review science lab safety rules here.

Get the plug-ins: Get Adobe Acrobat Reader and Get Quicktime Player. (The QuickTime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE Earth Systems Science core.

 


Updated October 24, 2008 by: Glen Westbroek

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