This year Lower Elementary is learning about the Composition of the Earth. This unit on physical geography follows the Sun and Earth study that we explored last year, and provides the children with a more intensive study of the planet. The goal is to provide an impressionistic understanding of the Earth’s composition and formation.
This week, the children were encouraged to think back to the Creation Story; how the world changed from a gaseous and liquid state to an increasingly solid one. We had a discussion about how the Earth cooled, and the heavy elements settled into the center, while the lighter ones rose to the surface. This was just like the experiment we did with oil, water and molasses, and how the molasses poured right through the lighter oil and water.
Students learned that the heavy inner part is called the barysphere. This includes the inner and outer core, plus the mantle, that we spoke of in the last lesson. The outer layer is called the lithosphere, which in the last lesson we called the crust. The thin layer of water surrounding the Earth is called the hydrosphere and the air around the Earth is called the atmosphere.