Why Is Ping Pong Balls?

Do you know why ping pong balls burn? Contrary to a popular myth, they are filled with air and not a flammable gas. The reason they burn is because they are made of celluloid. Celluloid is a flammable polymer, much like nitrocellulose of guncotton.

What did ping pong balls used to be made of?

At the end of the 19th century, when ping-pong was coming into its own, the ball was generally made of string, rubber, or sometimes even a used champagne cork.

Is there a difference between ping pong balls and table tennis balls?

Official ping pong balls are slightly larger than table tennis balls. Ping pong = 3.7mm in diameter, while table tennis = 3.4mm diameter.