Blog 8: Physics That Will Make Your Hair Stand Up

When my team and I played in a summer volleyball tournament in Reno, we experienced a lot of static electricity. Every time we walked through the lobby and touched a metal surface, we would get shocked. We even got shocked every time we went into our huddle after we shook hands with the other team and during a time out. My friend, Ali, was especially affected by the dry air and the static friction. Her hair would often stand up when we played.

Through the past few chapters we have been learning about, I now understand why we get shocked and how drier conditions cause an electric charge to stay in the air. When we dragged our feet on the lobby carpet or ran around the court, we picked up or released extra electrons to or from the floor. This gave us a positive or negative charge, so in order to become neutral again we gave off or accepted electrons from the next object we touch. This static build up happens even here in Hawaii, but we are more likely to get shocked in a drier place like Reno because Hawaii's air contains a lot of water which doesn't hold as much charge as drier air, without water vapor. Ali's hair stood up because they all became charged through static friction, so each strand repelled each other.

Blog 7: More Passing Physics

This past week I had practice almost everyday, so I had a lot of time to reflect about the physics of volleyball. Since we were learning about moment of inertia, I started to apply it to some of my volleyball technique. We learned that objects with the same mass have a greater moment of inertia if they have a large radius, or their mass is more spread apart. When I dive to get a ball, in order to stand up quicker, I either roll to the side and stand up or roll back over my shoulder. These maneuvers require quick rotation to stand up faster. I realized that the more I compact my body when I roll, the faster I can stand up and be ready for the next ball. My rotation would be faster because the radius used to calculate moment of inertia would be smaller, than if if my arms and legs were straight out. This is a picture of me right before I go into a roll.


In dance, we do a similar roll to the roll over the shoulder I do in volleyball, but for the dance row, the goal is to keep your legs as straight as possible. Since this increases the radius for the moment of inertia, this roll requires more torque and is not as fast as the volleyball roll.