Why can a pin go through a balloon without popping? Something to do with a semi-permeable membrane...?

Question

So why can a pin go through a balloon without popping in a certain way? in my class my teacher demonstrated this and I don't understand how it does that . We are learning about semi-permeable membranes and what not. How does it work???

Answer 1

Just to tie together the first response with the second and third response you received:

The tape on the balloon keeps the rubber from ripping when the pin is stuck into it. Unlike the rubber of the balloon, the tape's plastic is not prone to ripping when stuck with a pin.

There is another way the trick can be done that is even more impressive. You need a very long needle for this (perhaps a meat skewer or a really sharp knitting needle). You start with a balloon that is not blown up too tight. In particular, the top of the balloon should not be stretched tight (you can recognize this, because the rubber at the top will appear darker where it has not been stretched thin due to being inflated).

Start by pushing the large needle through the area at the top of the balloon where the rubber is not stretched. Because the rubber is not under tension, it will not rip and deflate the balloon.

Then push the needle farther and farther into the balloon until the point i at the bottom, near the mouth of the balloon. Here, again, the rubber is not stretched tight, so you can push the needle the rest of the way through, so that you have pierced the balloon in two places and it has not exploded. (It will, however, lose air slowly, so if you put the pierced balloon on display for a long time, it will eventually shrink to its uninflated size.)

Answer 2

It has nothing to do with semipermeable membranes.

The reason balloons pop is that when you stick them with a pin, you make a little hole in the balloon. The air in the balloon pushing on the rubber forces the hole open some more, often causing it to rapidly rip apart. thus it pops.

If a balloon isn't very highly pressurized (that is, you don't inflate it way too much), and you push the pin in carefully, the pressure inside the balloon won't cause the hole made by the pin to rip open more. And so it wont pop.

Answer 3

When we did this experiment in class, our teacher put a piece of tape on the balloon, then poked the needle through the tape.

Answer 4

an age old "trick" not just a piece of tape, but cross two pieces of tape. Carefully push the pin through, and if quick more than once. (thank you Mark Wilson)

Answer 5

Just paste a transparent tape on it and presto! you have a balloon trick. Your teacher is probably pulling your leg (figuratively).