Bladder Glass
   The bladder demonstration is a variant of the  Palm Glass demonstration. Instead of atmospheric pressure holding a hand on the top of an evacuated glass jar, open at both ends, a piece of animal bladder is tied over the upper opening of the glass, and the glass exhausted until the membrane bursts inward with a bang. This seemingly simple effect is mentioned in the majority of nineteenth century textbooks.  

   The apparatus I photographed at Washington and Lee University in Lexington, Virginia in the early 1980s. It had clearly been waiting since its last use sixty or seventy years before to be rediscovered.

Return to Pneumatics Home Page

Return to Home Page