Wednesday, June 13, 2007

Electricity - Episode 25

Electrons and protons are tiny, but they can move large objects! Watch several demonstrations showing the power and behavior of electrons, electricity, and their response to electromagnetic waves.

Science Theater Episode 25: Electricity


Carolyn said...

He does not explain WHY a wood be attraacted to a magnetized metal rod.

Dr. Matt J. Carlson said...

Yes, and I greatly regret that, not one of my best episodes really it is a bit scattered.

The basic idea is that there are positive and negative charges in the piece of wood. Electricity is the movement of charge. When a charged rod is held near the wood, some of the charges on the wood are attracted to the rod, others are repelled. The charges attracted to the rod move closer to the rod and are thus produce more "force" than the charges repelled by the rod - and the board moves toward the rod.

PS. Note that the charges in the wood are only able to move a tiny, tiny amount since wood does not conduct charge very well at all.

PPS. I think the rod was actually plastic, but it still held a charge.