Inertia Coin Tower Trick

 Overview 

Inertia can be found in everywhere in our daily life. But what exactly it is? Our experiment Inertia Coin Tower Trick is designed to give you a vivid demonstration. The required materials are just a ruler and some coins.

Age: 3+      Time: <10min

 Safety 

1. Be careful that kids swallowing coins.
2. Adult supervision.
3. Hold the ruler firmly in case throw it away.

 Materials List 

• Coins
• Ruler

 Instruction 

Step 1/2 – Stack several coins on any flat platform.

Step 2/2 – Use a ruler to quickly hit the bottom of the coin. You will find the bottom coin of a stack is hit away but the upper one.

 Troubleshooting 

Why did I break the coins stack?
- When you are hitting the coin, make sure that the ruler should move as close to the flat platform and fast as possible. The ruler cannot be tilted.

 Scientific Description 

What behind this Inertia coin tower is the Inertia that comes from Newton's first law of motion, relating that in an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force. This means that the coins tower wants to stay in their stacked position whenever an outside force is exerted on them. the ruler hit out the bottom coin but the upper part of the tower wants to remain rest just as before, a stacked position. In other words, this is where friction becomes come into play. Friction is a sticky force that occurs when two objects rub against each other. If you push or pull slowly friction helps pull or push the tower along with the bottom coin. But If you push or pull quickly, the coins still rub, but the friction force doesn't have time to get the stack moving. So the coin is hit out without pulling the tower with it. And the tower drops, almost perfectly, into the spot that it was before.
The washing machine is designed on Newton's first law of motion.

 Extensions 

How many coins can we stack? Does the amount of coin affect the result? Can you hit two at a time, or even more? Can you find something to replace the coin?