What you need:
A balloon
A wooden skewer (a slim pointy stick)
Vegetable oil
Marker
What to do:
1. With the marker, draw about ten dots on the surface of the uninflated balloon. These dots need to be large, roughly 2 cm in diameter. Make sure you cover the surface of the balloon evenly, and include its bottom and top areas too.
2. Now, inflate the balloon until it is almost completely full of air. Then carefully, let out about one third of the air. Knot its mouth.
3. Rub a few drops of vegetable oil over the wooden skewer.
4. You may notice that the dots you drew have been stretched out in a few places. But in other places, the stretching is not so pronounced. Keep your eye on any one of the lesser stretched dots.
5. Push the skewer in gently into the bottom of the balloon where the rubber is thick (be slow about this: don’t poke the balloon hard) and then gently, push it out of the lesser-stretched dot you chose.
What happens:
If all goes well, the balloon does not pop! It does gradually deflate though once you (slowly!) remove the skewer because the air leaks out from the holes.
Why?
The points on the balloon where the dots are less stretched out are the points of least strain.
Balloons are made of long chains of molecules known as polymers. These chain structures are elastic and allow the balloon to stretch. As the balloon is filled with air, the polymer chains stretch out. The more air you fill, the more stress these chains undergo. The slightest tear at one point can cause the entire chain to break and try to rush back to its original shape. That’s how a balloon usually pops.
But there are areas on the balloon (shown by the dots you drew) where these chains are not so stressed. Those are the areas you pierce. And the polymer chains do not break with a bang because they are not stretched too hard. This prevents the air from rushing out and the balloon from rupturing.
Picture Credit : Google
