The document discusses the Earth's internal energy and how it causes tectonic plate movement and related geological phenomena. The main points are: 1) The Earth has internal heat from radioactive elements and impacts that causes plate tectonics and results in volcanoes, earthquakes, and mountain building. 2) Alfred Wegener proposed continental drift in 1912 to explain how the continents were once joined together before drifting apart, as evidenced by matching continental shelves. 3) The Earth's solid crust is made up of tectonic plates that move due to convection currents in the mantle, resulting in earthquakes and volcanic activity at plate boundaries.

1. UNIT 8: THE EARTH’S INTERNAL ENERGY