This engaging activity introduces students to the concept of albedo and how albedo relates to Earth's energy balance.
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Positive and negative aspects of the model should be discussed beforehand with students. In particular, what do the popcorn kernels represent? Why are there 100 of them per trial? The text says "energy packets," which isn't concrete enough for students to grasp. In fact, each kernel represents 1% (which is why there are 100 kernels) of incoming solar radiation that will be reflected and absorbed by each type of land surface. How many kernels fall on each type of surface depends on its extent (area). Teachers might ask
students to predict which land surface type they think will have the most corn kernels landing on it? Which will have the fewest?
Have maps and containers with 100 popcorn kernels prepared before students do the activity. Explain to students what the kernels represent.
Albedo is the reflectivity of solar radiation by a given surface. This albedo is different over the ocean versus over snow and vegetation. The activity uses a very simple model for students to explore how the albedo of different land surfaces affects Earth's energy balance and climate change.
Students use a world map of global biomes and energy packets represented by popcorn kernels to explore and calculate the average yearly percentage of energy that is absorbed or reflected. Then they predict what will happen as Earth's snow and ice cover decrease due to climate change.
In this activity, students predict how climate change is influencing the amount of snow and ice cover, which, in tun, changes Earth's albedo.
Comments from expert scientist: This activity tries to explain the concept of Earth's albedo in a very simplified manner using easily available materials like popcorn kernels, world map (which is given in the activity material), etc. This interesting approach makes this concept easy to grasp by young learners.
The lesson is a good example of active learning. Students take data, do some simple calculations, and compute the differences between the amount of energy reflected and absorbed by different types of biomes.
The results of the investigation are striking and easy for students to understand. The activity will lead students to use their data to form their own ideas and conclusions about the role of ice and oceans in climate change instead of learning about these concepts from a lecture or reading.
The student handouts are attractive and written at an appropriate level for 6 - 12 grade students. A PowerPoint presentation with good images and text is provided. A modest amount of background information and a glossary are provided for both teachers and students.