You might have clothes, like a hat or a warm, cozy sweater, that are made of wool. You might even know that a lot of wool comes from sheep! But do you know how wool goes from growing on a sheep to being made into a sweater?

Howcast - Learn how to make Minecraft shears with this gameplay tutorial.

Gravity and erosion are major factors in changing the shape of the surface of Earth. The different types of erosion, and the major types of mass movements caused by gravity are discussed in this video. Other terminology includes:...