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EDS 1021Week 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
1. After completing the background reading for this assignment, go to “The Atmospheric
Greenhouse Effect” simulation on the PhET simulations website at:
https://phet.colorado.edu/en/simulation/legacy/greenhouse. Click the play arrow on the
simulation graphic to run the web-based simulation or click DOWNLOAD to run the
simulation locally on your device.
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). Theterm 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.
Before completing the experiment, write down a hypothesis, based on your current
understanding, that predicts the correlation between the concentration of greenhouse gases in
the atmosphere and 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 equilibriumtemperature 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.
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.
i.
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.
c.
Click the button next to Infrared Photon, underneath the photon gun.
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.
