How Does It Work
The secret is to use the portion of the balloon where the rubber molecules are under the least amount of stress or strain. If you could see the rubber that makes up a balloon on a microscopic level, you would see many long strands or chains of molecules. These long strands of molecules are called polymers, and the elasticity of these polymer chains causes rubber to stretch. Blowing up the balloon stretches these strands of polymer chains.
After drawing on the balloon with the Sharpie marker, you probably noticed that the dots on either end of the balloon were relatively small in comparison to the enlarged dots in the middle section of the balloon. You’ve just uncovered the area of least stress—the ends of the balloon. You wisely chose to pierce the balloon at a point where the polymer molecules were stretched out the least. The long strands of molecules stretched around the skewer and kept the air inside the balloon from rushing out. When you removed the skewer, you felt the air leaking out through the holes where the polymer strands were pushed apart. Eventually the balloon deflated, but it never popped, right?
Trying to pierce the balloon in the middle section is nearly impossible unless you have some help from a piece of clear tape. Normally, the long chains of rubber molecules are under so much stress or tension that they tear easily with the slightest puncture. The clear tape helps to hold the rubber molecules in place, preventing them from tearing apart when the balloon is punctured. In an attempt to fool the people who know how to push a skewer through the ends of a balloon, magicians will secretly place pieces of clear tape in the middle section of a balloon to keep the balloon from popping when they puncture the balloon in this “forbidden” area. It’s just another way to make even the smartest people say, “How did you do that?”
Aside from learning about the science of polymers, the Skewer Through the Balloon activity can be used as a great way to demonstrate a life lesson on how to approach a potentially stressful situation. The key to approaching any stressful situation is to find the area of least stress and to use this as an entry point as you attempt to relieve the tension. In other words, every stressful situation has a “best point of entry” and requires a good exit strategy if you are going to be successful in diffusing the potentially volatile situation. It’s a great object lesson at any age!
