22 Get Moving!

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Get Moving! by LAURA MAWER

Chapter 1 Push and Pull Can you see a force? No, you cannot. But you can see what a force does. Forces make things move. The stronger the force, the faster or farther something moves. There are two kinds of forces. They are push and pull. A push moves something away from you. A pull moves something toward you. We use push and pull forces every day. Throwing a ball is a kind of push. If you throw the ball hard, it will fly fast in the air.

Gravity and friction are forces that pull. Let's say you throw a ball to your dog. Your dog races to catch the ball. He misses it. The ball drops to the ground. What force pulls the ball to the ground? Gravity does. When the ball hits the ground, it may roll. What would make it stop? The answer is friction. Friction happens when two things touch each other. Let's say one of the things is moving, and the other is still. Friction pulls on the moving thing to stop.

Chapter 2 Tools That Push and Pull Bats are tools that push. Think about it. What happens when a bat hits a baseball? The bat pushes the baseball away. If the ball is hit lightly, it may not go far. But if the ball is hit hard, it could go out of the park!

Hammers are tools that push, too. A park worker might fix a broken park bench with a hammer. The worker could use the hammer to hit a nail into the wood. The hammer would give the nail a big push. Then the bench would be safe to sit on again. A hammer could also be used to pull. The worker could pull out a nail. He could use the claw end of the hammer.