Newton's three laws describe how objects move.

**1. Inertia:** An object at rest stays at rest, and an object in motion stays in motion with the same speed and direction *unless* acted upon by a force. Example: A soccer ball sits still until someone kicks it.

**2. Acceleration:** The force needed to accelerate an object is proportional to its mass and acceleration. Force = Mass x Acceleration (F=ma). A heavier wagon requires more force to pull at the same speed than a light one.

**3. Action-Reaction:** For every action, there is an equal and opposite reaction. When you jump, you push down on the Earth (action), and the Earth pushes you upwards (reaction) launching you into the air. This works because the Earth's much larger mass means your effect on it is minimal.
