Forces and Magnets
A force is a push or a pull that can change an object's speed, direction, or shape.
Magnets
Magnets have a north and south pole. Opposite poles attract; like poles repel. Magnetic force can act without direct contact, unlike most other pushes and pulls.
Friction
Friction is a force that slows things down when two surfaces rub together — it's why a ball rolling on grass stops sooner than one rolling on ice.