Earth’s Internal Heat Engine Very hot material from the core heats the materials above. The hot material expands and moves upward, and cools as it nears the surface. The cold crust is then pushed back down at plate boundaries. Image from: wps.prenhall.com/.../1269/1300245/18fig12.gif Fig. 1.6
www.adonline.id.au/plantevol/continents.htm Movement of the Continents: The continents have not always been where they are now. Over time they drifted across the surface of the Earth, and continue to do so today.
How Volcanoes Form Deep in the earth it is so hot that rocks melt. The melted rock is called magma. The magma is lighter than the rocks around it so it rises. Sometimes it finds a crack or hole in the earth’s crust and bursts through.