- from Volcanoes
The roots of volcanoes are in a layer called the mantle.
They can be 40 to 120 miles inside the Earth. Temperatures down there get as hot as 4,000°F. That’s so hot, rock melts like chocolate on a summer day down there! The melted rock becomes thick, flowing stuff called magma. Magma is lighter than the solid rock around it. So, it pushes up through cracks in the Earth. Wherever magma comes out, volcanoes form and grow. Magma that comes out of the ground is called lava. As lava cools, it turns into different kinds of rock.