Things Required:
Two clear drinking glasses
Saucer
Water
Coin
Directions:
Be theatrical. Make your audience focus their attention on your magical skills, props, and presentation. Place the base of a clear drinking glass over a coin.
Cover the mouth of the glass with a small saucer (the saucer prevents people from seeing straight down into the glass). From the side, your audience members will observe the coin. Make sure everyone can see the coin.
Now tilt back the saucer and fill the glass with water. Again, cover up the mouth of the glass with the saucer. Can the audience still see the coin? What happened to it?
This Is What Happens:
It’s those bending light rays again. The image of the coin travels along straight-line paths. When the glass is empty (actually it’s filled with air), there is little distortion and the rays travel a mostly straight path from the coin to your eyes. The water changes things.
Now, the light rays first travel in water. When they strike the side of the glass, some of them are bent and travel up the side of the glass. The light rays that do escape from the glass are bent so much that they travel almost straight up and are blocked by the part of the saucer that extends past the mouth of the glass. Since the rays carrying the image of the coin can’t get to your eyes, the object has “disappeared”.
