# If I put a ping pong ball in a vacuum, would it pop?

If I put a ping pong ball in a vacuum, would it pop? If so, at what point would it happen? Any standard table ping pong ball is acceptable.

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if it has air inside, yes. – yayu Apr 18 '11 at 15:51
So you're saying the shell of a ping pong ball wouldn't stand up to the pressure of a vacuum? – Nick Larsen Apr 18 '11 at 15:59
@NickLarsen now that will involve quantitative calculations. You must know the tensile strength of the material that makes the shell of ball. If the pressure inside is approximately atmospheric so it doesn't collapse or pop in air, then you would need to know the pressure of the partial vacuum (0 Torr in case of full vacuum, if that's possible), and find if the material can withstand such a pressure difference. In general, you can safely say that normal materials such as plastic wouldn't withstand the pressure gradients between say, a sputter ion vacuum on one side and air. – yayu Apr 18 '11 at 16:03
@yayu, I don't know the tensile strength of the ball, I just want to know if trying to make this happen is worth the effort. If you wrap up what you just said in an answer, I'd be more than happy to accept it under the assumption that it is worth the effort. – Nick Larsen Apr 18 '11 at 16:08
@NickLarsen I think it will pop. Check edit in my answer. – yayu Apr 18 '11 at 16:21

The answer to your question is "no". A quick web search for "ping-pong vacuum" yields a wealth of experimental evidence, in the form of articles with photographs about cannons that operate by putting ping-pong balls in vacuum and selectively releasing the vacuum.

Here are some videos of demonstrations. Note that the balls don't pop before being fired.

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Damn it, I just wasted like an hour. – Nick Larsen Apr 22 '11 at 14:05
Do thy use vacuum or are they sucessful without really trying? What I saw in those videos vaccum cleaners were used. Those have a "vacuum of about 100 to maybe 150 mBar. – Georg Apr 22 '11 at 19:16

Probably not - but without knowing the details of the specific ping-pong ball it's hard to tell.
There may be an international standard for ping-pong balls who would be happy to tell you!

The interesting part about the question is scaling laws. In a vacuum there is a pressure of one atmosphere (15psi or 10tons/m^2) acting outward on the inside of the ball.

BUT there aren't all that many square meters (or even square inches) on a ping-pong ball so the actual force is really quite low.

A sphere is a good shape for resisting this force, the most likely failure is the glue seam that holds the two halves together. And a ball has to survive the force of being hit pretty hard by a bat so the glue line is reasonably strong.

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It's not that hard to crack a ping-pong ball if you're really smacking it :-P (yes this is based on experience). It does indeed tend to crack along the seam, but not always. – David Z Apr 18 '11 at 18:04