The Balloon Trick

 

Materials: 

balloon

long needle

oil

Procedure: 

Blow up a balloon to about 2/3 it's maximum size and tie a knot in the end.  Place a little oil on the end of the needle and on the far end of the balloon  (this allows the needle slide through the balloon easier).  Slowly push the needle into the balloon.  If the needle is sufficiently  sharp and smooth it will not tear the rubber but will slide between the polymer chains, allowing them to stretch  around the needle.  The needle should then pushed through the balloon until it comes through  the other side near the knotted end.

Hint: 

Discussion: 

On a molecular level, a polymer is a lot like a long paper clip chain.  Each paper clip represents a simple molecule called a monomer ("mono" means one and "meros" means unit).  The monomers link together to form a long molecular chain called a polymer ("poly" mean many).  Natural rubber is a polymer composed of repeating units of the monomer isoprene:

CH2=CHCH=CH2

CH3

The polymer chains in rubber are folded and are joined to each other in a network structure that imparts a high degree of flexibility.  Magicians take advantage of this characteristic in the needle-through-the balloon-trick.

 

 

To schedule a demonstration, please send an email to the demonstration lab.

 

Contact:

Eric Camp

Lecture Demonstration Technician

Bagley Hall 171

(206) 543-1606

ericcamp@uw.edu

 

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