I allowed my students to create an edible Earth in order to teach them about the layers of the Earth and to introduce plate tectonics.
I introduced this lesson by asking the students if they were familiar with the story, “Journey to the Center of the Earth.” Most students indicated that they were familiar with the story. We discussed the fact that many Science fiction movies are based on factual information; however, there is also fiction in the story. This is the reason why it is in the genre of Science fiction. I also asked the students to share some information with me about fossils. I asked the students to think about the reason why similar fossils are found on different continents. I informed the students that we were going to create models that explain how the interior of the Earth is actually structured.
The students were highly engaged in this lesson. In this activity, students created an edible model of the layers of the Earth using marshmallows, crispy rice cereal, butter, a gum drop, and chocolate syrup. The interior of this model is very similar to making Kellogg's® Rice Krispies Treats®. First, the students placed a red gum drop inside the middle of a large marshmallow. Then, students stirred cereal into marshmallows and melted butter. This mixture was then rolled into a ball around the gum drop which was inside of the large marshmallow. After that, students covered the cereal ball with the type of chocolate syrup that hardens. When cut in half, students saw that this model represented the layers of the Earth, namely, the inner core, the outer core, the mantle, and the crust. Students then used a small tube of decorative cake icing to draw tectonic plate boundaries on the model. This model demonstrated that the Earth is made of layers and covered in tectonic plates. Students also created individual drawings of their group model with labels of the layers of the Earth. Information about tectonic plates was also included on this drawing. The goals of my lesson were met. The evidence of this is the individual drawings the students made of their group model.
During the “wrap-up” discussion at end of the class, I again reminded students about the reason models are used. I also showed them a model of Earth in their textbook. Several students referenced the fact that the size of the layers of their models was similar to the layers in the textbook, which caused me to believe that my lesson was effective. We also discussed Pangea, and the theory that the tectonic plates have drifted over time. This is the reason that similar fossils are found on different continents. The students are now ready to be introduced to the theory of plate tectonics, namely, mantle circulation, divergent/convergent/transform fault boundaries, earthquakes, and volcanoes. In the future, I will also include information about a recent volcano or earthquake to provide a real world connection.
