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As part of our volcano unit study, we learned a bit about plate tectonics.
As you may be aware, the top layer of the earth, called the crust, is covered in plates, called tectonic plates, that fit together like a jigsaw puzzle. However, unlike a jigsaw puzzle, the tectonic plates on the earth’s surface are in constant motion.
The place where two plates meet is called a boundary, and geologists classify plate boundaries into one of three kinds: convergent, divergent, and transform.
We did a hands-on geology lesson to learn about the three different plate boundaries and how they relate to volcanoes and earthquakes.
Three types of plate boundaries
Plate boundaries occur where two (or more) tectonic plates meet.
Geologists classify plate boundaries into one of three categories: convergent, divergent, and transform.
Convergent boundaries occur where two plates move toward each other and collide. Typically, when two plates converge, the thinner plate will sink under the thicker plate in a process called subduction. Convergent boundaries are also responsible for creating some of the tallest mountains on earth, such as K2 and Mount Everest.
Divergent boundaries occur where two plates move away from each other. This creates an opening where molten rock can erupt, forming new crust. The Mid-Atlantic Ridge, a mostly underwater mountain range in the Atlantic Ocean, was created due to a divergent plate boundary.
Transform boundaries occur where two plates slide past each other. A well-known transform plate boundary is the San Andreas Fault in California, which is responsible for many of the state’s earthquakes.
Hands-On Activity to Model Plate Boundaries
For this activity, we used graham crackers to model the tectonic plates and strawberry jam to model the earth’s mantle (the layer right beneath the earth’s crust), which is largely made up of magma (hot, liquid and semi-liquid rocks). We also used three small plates.
My daughter started by scooping some jam onto the plates.
Then I had her grab two
graham crackers tectonic plates. I named one of the boundary types and asked her to show me how the plates move at that boundary.
In the image below, she was sliding the graham crackers by each other to show a transform boundary.
And in the next image, she pulled the two tectonic plates apart from each other to show a divergent boundary.
At the end, we labeled the three types of plate boundaries.
And that was a simple, yet effective, hands-on way to teach about plate boundaries.