Place a coin on the table. Place a glass on top. You'll be able to see the coin. Now on pouring water in the glass the coin will disappear. However, on placing a drop of water on the coin, the coin will reappear. On shining a laser beam on the coin you will see three images -- one coming directly from the coin, other will bounce from the other side of the glass and the third will be a bent refractive image.
http://arvindguptatoys.com/toys/Magicalcoin.html This work was supported by IUCAA and Tata Trust. Thi
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