Just 4 Kids
This month's head-scratching puzzler
Here's a trick to amaze and surprise your friends:
Turn one coin into two and make one of the coins float as well!
What you will need:
- a glass
- water
- a saucer
- a coin
How to do the trick:
Fill a glass about 2/3 full of water and drop a coin into the glass. Next, place a saucer over the glass and carefully turn the glass over. Invite your friends to look down into the glass. Incredibly, they will see not one coin, but two - one resting on the saucer at the "bottom" of the glass, and one "floating" on top of the water!
How this trick works:
The reason you see two coins when only one coin really exists has to do with the way light bends when it travels through different substances. This is called refraction.
When the light rays reflected by the coin leave the water, they bend slightly before they enter your eye. However, your brain doesn't know that. When you see that phantom coin floating near the top of the water, it is because your brain has created an image of the coin where the light rays would have come from if they had not been bent.
For another example of refraction, look at the way drinking straws seem to bend at the point where they enter the water in a glass.