Balloon Kabobs

 

 

 

 

 

DESCRIPTION:
In this demo, a skewer is pierced through a balloon without popping it. The balloon is made from a rubber polymer. The polymer is made of many long, elastic, overlapping chains, very similar to spaghetti. When a skewer pierces the balloon, these chains are stretched and pushed open to make a hole for the skewer and the balloon does not pop. It is important to pierce the balloon near the bottom & top, where the rubber has the least amount of stress. The polymer is more able to stretch and rearrange, allowing the skewer to pass through.

CONCEPTS COVERED:
polymers
physical change

MATERIALS NEEDED:
– bamboo skewer (lightly sanded to get rid of any splinters)
– balloon
– Vaseline or cooking oil

PROCEDURE:
1. Blow up balloon about ¾ of the way, tie off
2. Coat the sharp end of the skewer lightly in Vaseline or cooking oil
3. Gently insert the sharp end of the skewer in the bottom of the balloon (where it was tied off) by gently pressing and twisting the skewer in
4. Gently press and twist the skewer through the top of the balloon

ADDITIONAL COMMENTS:
This can also be done with zippered sandwich bags full of water and pencils. It works best to skewer the least stressed parts of the balloon – the sides are under more stress and will pop easier. The balloon may deflate if left to sit, but it won’t pop.

SAFETY:
Safety goggles should be worn at all times.

REFERENCES:
“Skewer Through Balloon.” Steve Spangler Science. Accessed 10 Sep 2011.
http://www.stevespanglerscience.com/experiment/skewer-through-balloon

STORY:
Two balloons could be blown up. Ask the students if you will be able to put the sharp skewer into the balloon without it popping. For the first balloon, lightly jab the side of the balloon so it pops. Then do the second one as described above.

Handout