Skewering Balloons (Demonstration)
(Reference: Sarguis, M., Sarguis, J. Fun with Chemistry: A Guidebook of K-12 Activities, Institute for Chemical Education: University of Wisconsin: Madison, WI, 1991.)
 

Polymers   :   Organic Polymers
 

Purpose:
Illustrate the properties of rubber or latex, specifically the interwined strands of polymer molecules which will stretch around the point of a skewer.
 

Safety:
Safety goggles should always be worn in the lab
 

Materials:
Balloons
Bamboo skewer
Vaseline, mineral oil, or some other lubricant
 

Procedure:
Inflate balloon and tie-off (donít fully inflate).  Coat skewer with lubricant.  Carefully insert skewer into the nipple end of the balloon and then pass through the tie end.  Pull the skewer out and the balloon will deflate.  If this is done through the side of the balloon it will burst.
 

Explanation:
The polymer strands are stretched, but more so on the middle of the balloon than the ends.  Since the ends arenít stretched as much they will allow the sharp point of the skewer to pass through.
 

Clean-up:
Discard balloon in trash; may be able to save skewer.
 
 

Ginger Chateauneuf, 2000.
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