Interactive Activity
Tango
EDS1021GreenhouseEffectActivity1.docxEDS 1021
Week 8 Interactive Activity
Atmospheric Greenhouse Effect
Objective
Using a simulation, apply the scientific method to investigate the atmospheric greenhouse effect and its role in atmospheric energy transfer.
Background Reading
Before attempting the activity, review “The Greenhouse Effect” in Chapter 19 of The Sciences, as well as the website Global Climate Change (NASA), to gain some background on the atmospheric greenhouse effect and its role in both atmospheric warming and climate change. The video NASA's Earth Minute: Gas Problem (YouTube, 1:24) provides a short descriptive summary of the important points.
Introduction to the Simulation
Simulation requirements: This interactive simulation is optimized for use on computers (MACs or PCs) and may not run on some tablets, notebooks, cell phones, or other devices. Running the simulation will require an updated version of Java software (free). If you do not or are not sure if you have Java on your computer, go to the Java Website . If you cannot get the simulation to run, consult The PhET Simulation Troubleshooting Guide on the course website.
2. Explore and experiment on the three different tabs (areas) of the simulation. While experimenting, think about how the energy transfer processes involved in the atmospheric greenhouse effect are being visualized in the simulation.
Greenhouse effect tab – Observe the effects of greenhouse gases on both incoming (solar) radiation and outgoing terrestrial (infrared) radiation and atmospheric temperature. Yellow stars simulate photons of incoming solar energy (visible radiation), while red stars simulate photons of outgoing terrestrial energy emitted from Earth’s surface (infrared radiation). The term photon describes a “packet” of electromagnetic radiation. You can simulate atmospheres with different concentrations of greenhouse gases at different times in Earth’s history, or manually adjust the concentration of greenhouse gases, and observe the effect on atmospheric temperature. Clouds may also be virtually placed in the atmosphere to observe their effects on air temperature.
Glass layers tab – Create a “greenhouse” by adding glass panes to the atmosphere and observing the effect of a virtual glass ceiling on atmospheric temperature.
Photon absorption tab –Experiment to determine the preference of different atmospheric gas molecules to absorb a certain type of radiation by shooting infrared or visible radiation at the molecules.
3. After getting oriented to the simulation, follow the steps below to perform four different experiments. Before beginning, be prepared to write down hypotheses and observations for the experiments.
Experiments
Experiment 1: The Atmospheric Greenhouse Effect and Temperatures Through History
In this experiment, you will observe the atmospheric greenhouse effect and how different concentrations of greenhouse gases at different times in Earth’s history affected atmospheric temperature.
1. Experiment setup: click on the Greenhouse Effect tab at the top of the simulation screen.
2. Experiment procedure:
a. Click Reset All at the bottom right of the screen. Click Yes in the box that pops up.
b. In the Greenhouse Gas Composition box, move the slider to none . The simulation will run automatically for an atmosphere with no greenhouse gases.
c. As the simulation runs, carefully observe the number and paths of both sunlight photons (also called solar, or visible radiation) and infrared photons (also called terrestrial, or infrared radiation), and the change in temperature on the thermometer. If needed, slow the simulation down in order to accurately observe what is happening. Write down your observations.
d. Allow the simulation to run until the thermometer settles on a temperature (when the atmosphere reaches equilibrium). Record this temperature. This is the equilibrium temperature of an atmosphere with no greenhouse gases or clouds. Note that the temperature may fluctuate slightly once it reaches equilibrium, so do not be concerned about the exactness of your recorded temperature.
e. Click the button for Today in the Atmosphere During... box. The simulation will now illustrate the atmospheric greenhouse effect and resulting atmospheric temperature for today’s atmosphere.
f. As the simulation runs, again carefully observe the number and paths of both sunlight photons and infrared photons, and the change in temperature on the thermometer. If needed, slow down the simulation in order to accurately observe what is happening. Note the difference in photon paths for the atmosphere with greenhouse gases compared to without. Write down your observations.
g. The greenhouse gases in the atmosphere are: water vapor (H2O), carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). “PPM” is the abbreviation for “parts per million.” Record the greenhouse gas composition values for CO2, CH4, N2O, and H2O.
h. Allow the simulation to run until the thermometer settles on a temperature (when the atmosphere reaches equilibrium). Record this temperature. Note that the temperature may fluctuate slightly once it reaches equilibrium, so do not be concerned about the exactness of your recorded temperature.
i. Click the button next to Ice Age in the Atmosphere During... box. The simulation will now illustrate the atmospheric greenhouse effect and resulting atmospheric temperature during an ice age.
j. Repeat the above steps f through h to make observations and record the equilibrium temperature for the atmosphere during an ice age.
Experiment 1 - Results and Conclusions
1. Based on your observations while conducting the experiment, formulate a written discussion that describes the effect of
a. The atmosphere (with or without greenhouse gases) on incoming energy from the sun
b. Atmospheric greenhouse gases on outgoing Earth energy
2. Compare the observed values of equilibrium temperature for each of the simulated atmospheres in Experiment 1. Then, formulate a written statement that generalizes the effect of greenhouse gases on the atmosphere’s equilibrium temperature.
Experiment 2: The Effect of Clouds on Atmospheric Temperature
In this experiment, you will observe the effect of clouds on atmospheric temperature.
Before completing the experiment, write down a hypothesis, based on your current understanding, that predicts the effect of clouds on atmospheric temperature.
1. Experiment setup: click on the Greenhouse Effect tab at the top of the simulation screen.
2. Experiment procedure:
a. Repeat steps a through d in Experiment 1. (Note that the equilibrium temperature should be the same as the one recorded in step d of Experiment 1).
b. In the Options box next to Number of Clouds, place three clouds into the atmosphere by clicking the up arrow three times, so that “3” is showing.
c. As the simulation runs, carefully observe the number and paths of both sunlight photons and infrared photons, as well as the change in temperature on the thermometer. If needed, slow down the simulation in order to accurately observe what is happening. Write down your observations.
d. 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 with clouds. Record this temperature.
Experiment 2 - Results and Conclusions
1. Based on your observations while conducting the experiment, formulate a written discussion that describes the effect of clouds on
a. Incoming energy from the sun
b. Outgoing Earth energy
2. Develop a written statement describing the effect of clouds on the equilibrium temperature of the atmosphere.
Experiment 3: Glass Layers
In this experiment, you will observe what happens to the air temperature in a real greenhouse, by placing virtual glass panes in the atmosphere.
Before completing the experiment, write down a hypothesis, based on your current understanding, that predicts the effects of the glass panes on atmospheric temperature.
1. Experiment setup: click on the Glass Layers tab at the top of the simulation screen.
2. Experiment procedure:
a. Click Reset All on the right side of the screen. The simulation will start running automatically for an atmosphere with no greenhouse gases and no panes of glass in the atmosphere.
b. As the simulation runs, carefully observe the number and paths of both sunlight photons (visible radiation) and infrared photons (terrestrial radiation), and the change in temperature on the thermometer. If needed, slow the simulation down in order to accurately observe what is happening. Write down your observations.
c. 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) |
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CH4 (methane) |
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CO2 (carbon dioxide) |
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H2O (water vapor) |
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O2 (oxygen) |
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N2 (nitrogen) |
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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.
ii. Based on the information prompted for in the experiment’s Procedure and Results and Conclusions section, clearly and succinctly summarize your observations, results, and conclusions for the experiment, and include any data collected and calculations made.
iii. Clearly and succinctly evaluate the correctness of your hypothesis based on the information presented in part ii above.
c. Include your full name and the date you completed the activity at the top of the document.
2. Submit your document (in either .docx or .pdf file format) as instructed in the assignment location within the Canvas course.
