Movement

Forces make things move! In science, a force is a push or a pull on an object as a result of its interaction with another object.

Take a look at the horses in the picture--they are interacting with the snow, the ground, and the sleigh they are pulling behind them. Inside the horses' bodies, muscles and other body parts are interacting to allow them to move.

What sorts of objects do you interact with on a regular basis? If you've used your muscles to push a box, you interacted with that box. We could also say that you exerted, or applied, a force on that box.

When you open a door, you are exerting a force on the door. When a tugboat pulls a ship into harbor, it's exerting a force on the ship. When a bicycle hits a bump in the road, the bicycle is exerting a force on the bump. A force is exerted anytime one thing pushes, pulls, or lifts something else.