2.  The Earth has several layers.  No feature on Earth is permanent. The Core  Inside layer of Earth  Made of nickel and iron  Has a liquid outer layer that surrounds the solid inner part.  Decay of radioactive elements in the core send heat through the other layers of the Earth.

3.  Middle layer of Earth  Reaches almost to the Earth’s surface.  Rocks in this layer move because of heat from the core.

4.  Outer layer of Earth  Made of the lightest materials  Only about 40 km (about 20 miles) thick.  The lithosphere is the rigid outer shell of the Earth that consists of the crust and part of the mantle.

5.  The constant movement of the oceans cause constant change in the Earth’s surface.

6.  The continents of Earth look as if they could fit together like a giant jigsaw puzzle.  A German scientist named Alfred Wegener came up with the Continental Drift Theory. This theory says that all the continents used to be together, but drifted apart over millions of years.

7.  The lithosphere is broken into sections called plates. When these plates move, they cause changes in the Earth’s surface, like volcanic eruptions, earthquakes, and creation and destruction of mountains. These plates collide, pull apart, or slide past each other very slowly. This is constantly happening.

8. Pangaea Scientists believe that the continents of Earth were once all connected in a super-continent called Pangaea. The continents actually appear to fit together like the pieces of a puzzle.

9. Over time, the plates have moved apart to form the Earth we live on today.