Albedo is a term that refers to a surface’s ability to reflect back radiation into the atmosphere. It is measured from 0 to 1. An object with a high albedo will reflect back a high percentage of the radiation it receives and absorb very little. An object with a low albedo will reflect back a low percentage of the radiation it received and absorb a lot. Lighter colored objects have a high albedo and dark colored objects have a low albedo. The absorption of radiation causes the surfaces to heat up more. This is why black car interiors get so hot in the summer! They have a very low albedo.
You can measure the albedo of different surfaces relative to each other with this simple experiment!
Supplies:
- Different colored paper. I used white, black and cardboard. (You can use ANYTHING you want! Just make sure they are flat.)
- Ice
- Sun
Directions:
- Place your objects outside in a sunny place. If you are using cardboard and paper, first back the paper with cardboard. You’ll see why this is important when you watch my video.
- Let the object heat up in the sun for at least 15 minutes. Longer is better.
- Place your ice cubes on the different objects or pieces of paper.
- Watch! The ice cubes should melt in order of lowest albedo to highest!
Albedo is very important to our Earth’s climate. A good example of albedo impacting our climate is the ice caps. The ice caps are shrinking. By nature, these have a high albedo because snow and ice reflect a lot of radiation. Due to global warming the ice caps are becoming smaller. As they shrink they cover less surface area and are replaced with sea water. Sea water has a very low albedo. This means we are replacing the “cooling” effect that the ice caps create by reflecting radiation away from the Earth and replacing it with a warming effect as sea water absorbs radiation and heat. This creates a cycle that continues to shrink our ice cap surface area, increase our sea water surface area and increase the Earth’s overall albedo. This currently is changing our Earth’s climate and will continue to impact it in the future.
Click on the links below if you’d like to learn more about the ice caps and how their loss is impacting our climate:
https://nsidc.org/cryosphere/seaice/processes/albedo.html
https://climate.nasa.gov/resources/education/pbs_modules/lesson2Engage/
https://www.gfdl.noaa.gov/bibliography/related_files/mw0901.pdf
