Posted Date: 02/27/2020
Students in 2nd grade have been learning about the Earth’s crust. As part of their unit, they used items to create a model of each layer of the Earth.
The crust is of two different types. One is the continental crust (under the land) and the other is the oceanic crust (under the ocean). The continental crust is thicker, 30 km (20 mi) to 50 km (30 mi) thick. It is mostly made of less dense, more felsic rocks, such as granite. The oceanic crust is thinner, 5 km (3 mi) to 10 km (6 mi) thick. It is made of denser, more mafic rocks, such as basalt.
The temperature of the crust increases with depth because of geothermal energy. Where the crust meets the mantle the temperatures can be between 200 °C (392 °F) to 400 °C (752 °F). The crust is the coldest layer because it is exposed to the atmosphere.