Things Move

The world around us is in motion, full of living and nonliving things that move in ways that can be predicted and described. Pushing, pulling, friction, and gravity are forces that affect objects at rest and in motion. This unit explains these forces, and it describes the movement of objects, including how forces can move things, stop them, and change their speed and direction. Knowing how and why things move allows us to work, play, get around, and complete everyday tasks.