http://www.wimp.com/demonstratescannon/

  We all should have been fortunate enough to have a physics professor like
  this one. :-)

  Gary Knutson


 I'm a bit surprised that the ping pong ball was sturdy enough to stand
 up to the vacuum without bursting.

 - Mark LaPierre

Now, I've got to put a ping pong ball in my bell jar and watch what
happens under vacuum. :-)

Gary Knutson

They are filled with oxygen.

The units are inches and psi

t is the thickness say .020
d is the internal diameter say 2 inches
p is the pressure in pounds per square inch = 14
f is the stress in psi

see the attached jpg.

p*d = 28

4t=.08

f = 350 psi stress piece of cake for Cellulose Nitrate

Cellulose Nitrate has a max tensile 48 to 55 MPa = megapascal

48 megapascal = 6,961 pound/square inch stress
to
55 megapascal = 7,977 pound/square inch stress


Paul Lamar

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