Ok let's face it everyone loves to watch a sharp skewer go through a balloon without popping
it. Under normal circumstances needles and balloons don't mix. However, with the right
technique it can be done and is sure to please the crowd! We will learn about polymers and
chains of molecules during this experiment.
1) Sharp BBQ Skewer (I prefer the bamboo kind from the supermarket)
2) Some good quality large latex balloons.
3) Petroleum Jelly, Baby Oil, or Cooking Oil
Watch Video: Needle Through Balloon
Process For Needle Through Balloon:
1) Blow up your balloon all the way until it's all the way inflated.
2) Let out about 1/3 of the air.
3) Tie the balloon off.
4) Get out your bamboo BBQ skewer / needle
5) Give the skewer a good liberal coating of the oil or petroleum jelly from the point to the
opposite end of the skewer.
6) Turn the balloon to the opposite end of the place where it is tied off and look for the dark
7) Put the pointed tip of the skewer through the darkest part of the balloon by putting gentle
pressure on it while twisting the skewer in one direction with your finger tips.
8) Once the skewer has pierced this end, move it through the inside of the balloon until you
hit the area where the balloon is tied. Gentle twist the skewer through this area and out the
The Science of Needle Through Balloon:
Congratulations you successfully put a needle through a balloon! The balloons we used are
comprised of a material called latex. Latex is stretchy because it is made of polymers.
Polymers are long chains of molecules cross linked together. In a balloon the polymer
molecules form something resembling an air proof web that can be stretched out when
blown up. Most things made of plastic are polymers.
The dark spots on the balloon are thicker than the rest of the balloon. This is the point where
the latex molecules are under the least amount of strain. The balloon fails to pop when a
sharp skewer is twisted through the dark spots because the polymers are pushed aside but
remain bonded by the cross-links - keeping the air inside. We put oil or petroleum jelly on
the skewer to ensure a smooth slide through the balloon. If you were to try and poke the
needle through the part of the balloon that was under the most severe strain or stretch (the
sides) the balloon would pop. Congratulations now go show all your friends how to put a
needle through a balloon!
Another Polymer Experiment
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