The principle of inertia is a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force. We are showing how this natural law works by conducting the coin inertia experiment, here is what you will need:
- Tall clear glass cup
- Water
- Small piece of cardboard
- At least five coins (quarters worked the best for us)
- Fill the glass about 3/4 of the way with water.
- Place the piece of cardboard on top of the glass, leaving an inch or two off the edge for you to flick.
- Stack your coins on the cardboard centered with glass.
- Now flick the cardboard!
This should send the piece of cardboard flying while dropping the coins into the glass of water. You can try this experiment with a different number of coins and different kinds, what do you think will happen?