What To Do
Get prepared by squeezing a little washing up liquid into a small container and get your skewer ready. Now blow up the balloon and tie a knot in it. Take the skewer and dip it in the washing up liquid and here comes the exciting bit. Hold the balloon at the knot and push the skewer into the balloon as close to the knot as possible. Hopefully it will not burst!
Now if you are feeling lucky you can try and push the skewer all the way through. Look at the top of the balloon and you will see a dark spot. Gently push the skewer all the way through the balloon and press it carefully against the inside of the top of the balloon and check its in the centre of this dark spot. Give the skewer a gentle twist and push as you do. If you are lucky then the skewer will emerge through the balloon without the balloon popping.
The Science
As a balloon is blown up the rubber is stretched. When you make a hole in the balloon using something sharp then the stretched rubber pulls on the balloon causing a rip and the balloon bursts. There are two places on a balloon however, where the rubber is not stretched; at the very top and near the knot. Because you placed the skewer through the balloon at these points, the balloon was not able to pop.
