This is a science experiment AND something to amaze your friends with at recess.
(It's also something cool to do to impress your relatives with at holiday time.)
The science part is the principle of INERTIA. All objects in the universe have inertia.
You can think of inertia as sort of "laziness." Objects at rest - that is, objects which aren't moving - tend to stay at rest. Objects which ARE moving tend to KEEP moving, unless they are stopped. SO, for instance, if you throw a ball, technically, it would go on forever, except that the air slows it to a stop.
Here's the trick/experiment.
- First, balance a coin on your elbow.
- Next, bring your arm down quickly to catch the coin in your hand. It may take some practice to get it right, so don't be discouraged. Don't give up! You'll get it!
WHY DOES THIS WORK?
Because the coin has INERTIA. Although gravity will pull it downwards, FIRST, inertia will make the coin tend to stay right where it is - hanging in the air for a brief moment - time enough for you to bring your arm down and catch it.
With enough practice, you'll be able even to stack more than one coin on your elbow!