ELI5: force

In elementary physics, a force is simply a push or a pull on an object that makes it move, stop, or change direction.

Whenever you interact with things around you, you are using force. If you want to move your toy car, you have to push it. If you want to open a door, you have to pull the handle. Without a force, things just stay where they are or keep moving the exact same way forever.

Here is what a force can do to everyday objects:

• Start movement: When you kick a stationary soccer ball, your foot applies a push that sends the ball flying across the grass.
• Stop movement: When you catch a thrown baseball, your hands use a force to stop the ball from moving.
• Change direction: When you hit a tennis ball with a racket, the force pushes the ball back the other way.
• Change shape: When you squeeze a piece of playdough, the push of your fingers squishes it into a new shape.

• Gravity: This is an invisible pull from the Earth that keeps your feet on the ground and makes an apple fall from a tree instead of floating away into the sky.
• Friction: This is a rubbing force that happens when two things slide against each other, like your sneakers gripping the floor or the brakes slowing down your bicycle.
• Magnetism: This is the special push or pull between magnets that lets you stick your drawings to the refrigerator.