In this activity, the students will add a variable for albedo to the greenhouse gases model. They will run experiments changing to determine the impact of changing the albedo.

• Review the concept of albedo
• Watch a video on creating a slider to control albedo
• Change the albedo variable and run experiments to see its effect.
• Watch a video showing an example of an experimental design
  

Review the concept of albedo

• In the Greenhouse Gas base model, 60% of the time, the radiation is simply reflected back to space, but 40% of the time a “heat” is generated, causing the temperature to increase.
  
• Students should reflect on this probability and learn that it is called albedo and is variable across the Earth, depending on the surface type.
  
• Ask the students, what do you think would happen if more solar energy were reflected instead of turning into heat?
  

Create a slider to control albedo 

Run experiments to see the effect of changing the albedo variable

• Use the Experimental Design form to sketch out your intention.
• Students should go into the code and change the variable and start the model again.
  
• Navigate down to the code, and find the Solar Energy tab. Discuss the meaning of the code relating to Solar Energy in the Forever block. There are three blocks of code. The one on the left describes how solar energy moves when the forever button is toggled. There is an if/else code block with another if/else code block nested within it. The solar energy will go down 1 step at a time, until reaching the ground (z=0). When it touches the ground, a random 60 out of 100 times the solar energy will be reflected (a “reflected energy” breed will be created). The rest of the time infra-red radiation will be created (the “heat” breed). This represents the average albedo (reflectivity) of the Earth: 60% of solar radiation is sent back into space, and the rest is absorbed and then later emitted as heat.
  
• Ask the students, do you think there are some surfaces that reflect more solar energy than others? Think about the colors of cars - which cars get warmer? Lighter colored surfaces reflect more heat than darker colored surfaces. Ice and snow are much lighter than other Earth surfaces and they reflect more solar energy.

Watch a video showing an example of an experimental design:

Quiz questions:

Reflection:

Upload your experimental design form and a link to your model in your portfolio in the section "SL Nova Projects- Earth" under the heading "Greenhouse Gases model with Albedo slider"