Modeling the Greenhouse Effect

Category: Simulation/Learning Cycle

Learning Objectives:

1. The student will simulate the greenhouse effect
2. The student will draw a model of what he/she thinks is happening
3. The student will draw inferences from the model and from other resources to determine possible outcomes of increased earth temperatures.

Materials, equipment and/or facilities:
For each group of students performing the lab you will need:

1. Two clear plastic storage boxes
2. Soil to cover the bottom of the boxes to about 3 cm.
3. Cardboard
4. Two laboratory thermometers
5. Heat lamp
6. Clear plastic wrap

Sequence and duration of each part of lesson:
Time: 30 minutes
Exploration:
Student groups should:

1. Fill the bottom of the 2 storage box with about 3 cm of soil.
2. Into each box insert a stiff piece of cardboard into the soil at about half the length of the box.
3. Use the cardboard to prop up the thermometer. The bulb of the thermometer should be facing up.
4. Cover one of the boxes with plastic wrap and leave the other uncovered.
5. Place both boxes underneath the heat lamp so that they are equidistant from the heat lamp.
6. Record the temperature in both boxes.
7. Turn on the heat lamp and wait 10 minutes.
8. Turn off the heat lamp and record the temperature in both boxes.

Concept Generalization:
Students should write answers to the following questions.

1. How did the temperatures differ between the covered box and the uncovered box?
   
2. What energy conversion was occurring in both boxes?
   
3. Assuming the same amount of energy was in both boxes, why were their temperatures different?
   
4. Which box would you say was most like the sun shining on the earth's atmosphere and why do you think that?
   
5. The effect on the covered box is called the greenhouse effect. Draw a model of what you think is occurring.

Application:

1. What is the 'cover' on the atmosphere? Why doesn't heat escape into space?
2. Knowing what you know about heat energy, explain why you think temperature at higher elevations is usually cooler?
3. In the earth's atmosphere carbon dioxide is one of the gasses that traps heat. Plants remove carbon dioxide from the air and replace it with oxygen. Burning of fuel produces carbon dioxide. What kinds of things are we doing on our planet that could cause the planet to heat up?
4. The possibility of earth temperatures increasing is called global warming. Why would an increase in average earth temperature be a problem? What effects could it have on other earth systems?