How To Pierce A Balloon Without It Popping

Step 1: You will need

Step 2: Aim

The aim of this experiment is to pierce the skin of a balloon without it popping.

Step 3: Method

Stretch the balloon with to make it easier to blow into. Blow steadily into the balloon.
Don't blow it up to its full size, and the experiment will be easier to perform.
Tie the balloon by wrapping it around a finger first, then tuck the end through the hole.

Pierce the balloon on the top at the spot where the colour is darkest. This is where it's less stretched.
Put a bit of petroleum jelly on the head of the balloon before the needle is pushed through. This reduces friction when the needle pierces the balloon's surface.
Push the skewer through the top of the balloon first, then out of the neck.

Step 4: Conclusion

Why did this happen?
Balloons are made up of lots of chains, called polymer chains, that are so small they are invisible to the naked eye. On the sides of the balloon, these polymer chains are stretched to their limit. At the neck of the balloon the polymers are much less stretched, so when pierced with a knitting needle, there is enough room to allow the needle in between the chains without breaking them.