Science Projects And Inventions

YOU NEED:

• An inflated balloon
• A pin
• A roll of cellophane tape

Whenever you pierce a balloon, it is natural for you to expect it to burst. Surprise your friends by saying that you can puncture a balloon three times without it bursting. What they probably don't know is that there are two spots on an inflated balloon where you can push in a pin without bursting the balloon. The first spot is alongside the mouth of the balloon. The other is directly opposite the balloon mouth. A third spot can be created by attaching a small piece of invisible cellophane tape on the side of the balloon. The balloon will not burst when a pin pierces the tape. You have just shown that you have punctured the balloon at the three spots without bursting it. Complete the trick by pricking the balloon at another spot, other than the one with the tape. This spot would be vulnerable and would explode the balloon once you pierce it.

HOW  DOES  IT  WORK?

 When a balloon is blown up it stretches and expands. The rubber it is made of gets thinner and weaker, but since there is an equal pull in every direction, the balloon stays together. Once you stick a pin in the balloon, a tear is made in the stretched material. The edges of the tear is pulled more strongly by the rest of Ihe material of the balloon at the edges of the tear. It expands so rapidly the balloon bursts. There are some spots in a blown-up balloon where the material is not stretched so thin. These are located near the mouth and bang opposite. Once you stick a pin here a tear is made, but the surrounding material doesn't exert pull that much.