This weekend was my Aunty's 50th Birthday, so to celebrate our family went to her favorite restaurant for dinner. We got there early to decorate the private party room, and it was the job of my cousins and I to strategically place all of the balloons around the room. However, after our physics lab in which we observed static friction after charging a balloon by rubbing it against someones head, I began to chase my little cousin around to show him how cool repelling balloons are.

When I rubbed the balloon against Roman's hair, the balloon picked up extra electrons and had a negative charge because it was charged by friction. Holding it near something neutral, like his arm, polarized the hairs on his arm (positive charges moved closer to the balloon because opposites attract) due to induction because the balloon had a negative charge in one area. The static charge built up and each of the hairs had a positive charge near the balloon, and things with the same charge repel each other. That is why the hair on his arm was standing up - the hairs wanted to get as far away as possible from the other hairs that had the same charge, but closer to the balloon that had the opposite charge. The same concept applied when I rubbed a second balloon on Roman's hair, so that it also became negatively charged, and held it near the other balloon. Because in the spots that were closest together both balloons had a negative charge, the balloons were trying to repel each other because the electrons were trying to get as far away from the other electrons as possible.

Roman thought these physics "tricks" were pretty cool and that I was some kind of magician, but really I'm just a physics student who learned that its not that hard to impress a 3 year old :)