outlets

Today after I went to karaoke with my family, I went to the bathroom to go take a shower. I pushed the power button but the radio didn't turn on. Then I realized that it wasn't plugged in and I felt like an idiot. So I plugged it in and realized that there was physics in the outlet. The average house outlet has 120 volts. Actually the difference in voltage between the two points of an outlet is 120 V. The outlet has three holes. Two of them make a complete circuit, which is why there is power when I plugged the radio in. The third hole is to keeps it grounded so that it doesn't short circuit. But it made me think of those caution signs. Like the ones on power plants and stuff that say danger high voltage. When I was little I used to think that it was super dangerous and that if i just touched it I would get shocked. But volts is actually a ratio of potential energy and charge. The more potential energy per coulomb, the more dangerous it is. But now I know better =] I never realized there could be so much physics in such an everyday household item like an outlet.