If you have a stack of objects, and you want to take the top one off, you can just knock it off. But what if you just want the bottom one off?
What you need:
16 quarters or other large, identical coins
What you do:
- Stack 15 quarters on top of one another on a table. How do you remove the bottom one, without touching any other quarters?
- Take one more quarter and place it on the table a few inches from the tower.
- Now use your finger to flick the quarter towards the stack of quarters so that it hits the bottom quarter and both shoot away.
- With good aim, you can continue this with the rest of the quarters in the tower.
This works because the coins all have inertia – they want to remain where they are, and will resist any movement. Hitting one coin out of the stack is easy because a single coin is light and has little inertia, but the tower itself is so heavy that even the force of another coin hitting its base is not enough to knock it over.
Have you ever seen a magician set a table, then quickly pull the tablecloth out from underneath the dishes, leaving the dishes right where they were? That isn’t “magic”, it’s science! The dishes are really heavy, so they have lots of inertia. And that means that even when the magician pulls on the tablecloth, the dishes want to stay where they are.
In fact, everything that we see and we think is “magic” is really just science that we don’t understand.
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