Allow the simulation to run until the thermometer settles on an equilibrium temperature. This is the equilibrium temperature of an atmosphere with no greenhouse gases or glass panes. Record this temperature. (It should be the same as the one recorded in step d of Experiment 1.)
d. In the Options box, next to Number of Glass Panes, place one glass pane into the atmosphere by clicking the up arrow once so that “1” is showing.
e. Repeat step b above.
f. Again, allow the simulation to run until the thermometer settles on an equilibrium temperature. This is the equilibrium temperature of an atmosphere with no greenhouse gases and one glass pane. Record this temperature.
Experiment 3 – Results and Conclusions
1. Based on your observations while conducting the experiment, formulate a written discussion that describes the effect of glass panes on
a. Incoming energy from the sun
b. Outgoing Earth energy
2. Based on your discussion above, explain why the term greenhouse is used to describe the effect of atmospheric gases, such as carbon dioxide and water vapor, on atmospheric temperature.
NOTE: If you are not entirely sure of the meaning of the term greenhouse, do some research on the topic before formulating your explanation.
Experiment 4: Photon Absorption
In this experiment, you will determine which gases in our atmosphere are greenhouse gases by “shooting” photons of both visible and infrared radiation at gas molecules and observing their reaction.
Before completing the experiment, write down a hypothesis, based on your current understanding, that predicts how each gas molecule will react when photons of visible or infrared energy are shot at it.
1. Experiment setup: click on the Photon Absorption tab at the top of the simulation screen.
2. Experiment procedure:
Construct a table like the one below. Complete the following steps to complete the table.
a. Click the button next to CH4 in the Atmospheric Gases box. A methane gas molecule now sits in the middle of the screen.
b. Click the button next to Infrared Photon, underneath the photon gun.
c. Using the slider underneath the gun, shoot 50 infrared photons at the molecule at a slow enough speed that allows you to observe what is happening while counting off the 50 photons at the same time.
d. As photons are emitted from the gun, observe that some of the photons pass through the molecule, and some are absorbed by the molecule. It will be obvious when a photon is absorbed by the molecule. As you count off the 50 photons, make a tick mark on a piece of paper each time a photon is absorbed.
e. Out of the 50 photons shot at the molecule, tally up the number of photons that were absorbed by the molecule, and record this value.
f. With the gun still loaded with infrared photons, repeat steps c through e above for the other four gases in the Atmospheric Gases box – CO2, H2O, O2 and N2.
g. Click the button next to Visible Photon, underneath the photon gun, to load the gun with visible photons to shoot at the gas molecules.
h. With the gun now loaded with visible photons, repeat steps c through e above for all five of the gases in the Atmospheric Gases box – CH4, CO2, H2O, O2 and N2.
| Gas Molecule | # of Infrared Photons Absorbed (out of 50) | # of Visible Photons Absorbed (out of 50) |
| CH4 (methane) | ||
| CO2 (carbon dioxide) | ||
| H2O (water vapor) | ||
| O2 (oxygen) | ||
| N2 (nitrogen) |
Experiment 4 – Results and Conclusions
1. Based only on your observations while conducting the experiment, formulate a written discussion that describes how oxygen and nitrogen (the two primary components of Earth’s atmosphere) interacted with both incoming solar radiation and outgoing Earth radiation.
2. Based only on your observations while conducting the experiment and the known properties of a greenhouse gas:
a. Identify which gases tested are greenhouse gases and explain how this was determined.
b. Identify which one of the gas tested is the most effective at “doing its job” as a greenhouse gas and explain how this was determined.
Activity Submission
1. Create a document containing a report for each experiment. Your document should contain four paragraphs, one for each experiment.
a. Title each paragraph with the corresponding name for each experiment, as it is stated in the headings for the experiments above (e.g., Experiment 1: The Atmospheric Greenhouse Effect and Temperatures Through History).
b. For each experiment report:
i. Clearly and succinctly present your hypothesis for the experiment.
