PhET Activity for MS-ESS3-3: The Greenhouse Effect

DIRECTIONS:
1. Click on the 'Waves' thumbnail in the center of the screen to enter the first simulation mode.
2. Click the 'Start Sunlight' button located in the center of the view.
3. Observe the yellow sunlight waves traveling from the sun to the Earth and the red infrared waves being emitted from the Earth's surface.
Spend 2-3 minutes freely exploring this 'Waves' view. Take note of the thermometer on the left, the controls in the right-hand panel, and the behavior of the energy waves. Do not change any settings yet.

QUESTION: Are you acquainted with the tools in this simulation?

DIRECTIONS:
1. Click the orange 'Reset' button in the bottom right corner to return to the default state.
2. In the right-hand panel, move the 'Greenhouse Gas Concentration' slider all the way to the left to the 'None' position.
3. Click the 'Start Sunlight' button.
4. Wait for the temperature shown on the thermometer to stop changing.

QUESTION: Without any greenhouse gases, what happens to most of the infrared radiation (heat) emitted by the Earth's surface?

DIRECTIONS:
1. Do not reset the simulation. It should still be running with no greenhouse gases.
2. In the right-hand panel, move the 'Greenhouse Gas Concentration' slider all the way to the right to the 'Lots' position.

QUESTION: Greenhouse gases in the atmosphere absorb outgoing ___ radiation and re-radiate it in all directions. This process traps heat and causes the surface ___ to increase.

(a)  

DIRECTIONS:
1. Click the orange 'Reset' button.
2. In the right panel, click the 'Ice Age' preset button.
3. Click 'Start Sunlight' and let the temperature stabilize. Note the temperature and the visual representation of the atmosphere.
4. Now, click the '1750' preset button and let the temperature stabilize.
5. Finally, click the '2020' preset button and let the temperature stabilize.

QUESTION: Arrange the following time periods in order from the LOWEST average global temperature to the HIGHEST, based on the simulation presets.

DIRECTIONS:
1. Click the orange 'Reset' button. A cloud is present by default.
2. Select the '2020' preset in the right panel.
3. Click 'Start Sunlight' and let the temperature stabilize with the cloud present.
4. Note the final temperature.
5. Now, uncheck the 'Cloud' checkbox in the bottom right to remove the cloud and observe the temperature change.

QUESTION: Clouds have a complex, dual effect on climate. What are the two opposing effects you observed?

DIRECTIONS:
1. At the bottom of the screen, click on the 'Photons' tab to switch models.
2. In the right panel, set the 'Greenhouse Gas Concentration' slider to a middle value.
3. Click the 'Start Sunlight' button.
4. At the bottom of the screen, click the 'Slow' radio button to slow down the simulation speed.

QUESTION: When an infrared photon hits a greenhouse gas molecule, it is absorbed and then (a)   .

DIRECTIONS:
1. Stay on the 'Photons' tab with the simulation running.
2. Ensure greenhouse gases are present (slider in the middle) and the simulation speed is set to 'Normal'.
3. Watch many sunlight photons (yellow) and infrared photons (red) as they travel through the atmosphere.

QUESTION: What is the primary difference in how an atmosphere with greenhouse gases interacts with sunlight versus infrared radiation?

DIRECTIONS:
1. At the bottom of the screen, click on the 'Layer Model' tab.
2. Ensure the 'Absorbing Layers' stepper in the right panel is set to 0.
3. Click the 'Start Sunlight' button.
4. Observe the surface temperature on the left once it stabilizes.

QUESTION: In the Layer Model, an 'Absorbing Layer' is an abstraction that represents the planet's ___. With zero layers, the surface temperature is very ___.

(a)  

DIRECTIONS:
1. Do not reset. The simulation should be running in the 'Layer Model' tab.
2. In the right panel, click the up arrow on the 'Absorbing Layers' stepper to add one layer. Observe the temperatures.
3. Click the up arrow again to add a second layer. Observe the temperatures.
4. Click the up arrow one last time to add a third layer. Observe all four temperatures.

QUESTION: In the Layer Model, what happens to the surface temperature as you add more absorbing layers?

DIRECTIONS:
1. Keep 3 absorbing layers set in the 'Layer Model' tab.
2. In the right panel, move the 'Surface Albedo' slider all the way to the left (value of 0.0). This represents a dark, absorbing surface. Let the temperature stabilize.
3. Now, move the 'Surface Albedo' slider all the way to the right (value of 0.9). This represents a light, reflective surface.

QUESTION: A surface with high albedo (like snow or ice) reflects more sunlight and results in a (a)   temperature.