Is there anything else that uses the same kind of plastic that the ping pong ball uses?

Ping pong balls are made out of plastic. Right? Wrong. They are made of celluloid, a colorless flammable material composed of nitrocellulose and camphor, the same ingredients used to make photographic film. Hence, reels of movie film and ping pong balls are made of the same stuff! Celluloid is used because it provides a stronger bounce than plastic. Ping-pong balls are very stiff and springy, and they lose only a small fraction of their energy when they bounce on a hard surface. PS: In the Jan/Feb, 2005 issue of USATT Magazine there is a very interesting article about how ping pong balls are actually made.

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