Making a Leyden Jar and Static Zapper

This could go with a discussion of static electricity, but since we talked about the invention of the Leyden jar when we discussed the history of electricity, we made it on a different day. The Leyden Jar is named after the university where it was first used (you say it "LIE-den" jar, if you are wondering) :) and this Robert Krampf video shows how to make one. It's basically just a device that can store and release a static electric charge---i.e., a simple capacitor. For our Leyden Jar, we covered the inside and the outside of a plastic cup with foil, and then made a long snake of foil coming out from under the inside foil. You charge the jar up using static (we rubbed a balloon over Malachi's hair 40-50 times and touched it to the collector, the ball of of foil at the end of the snake. You cAn hear a kind of crackle as it's working.) and then you can discharge it when you touch your finger, or another foil snake, to the collector ball. It's quite fun to see how much charge you can build up (Robert Krampf says it's 25,000 volts!)

You can even see a tiny purple spark in this picture!

This "zapper" works the same way, but this time it's made with a styrofoam cup and plate and a foil pie pan. Directions for making the zapper are here.

Static Electricity and Ions

We started this unit with static electricity, and to understand that, you first have to understand ions. We learned about ions when we studied nuclear energy, but it was good for us to review it. (I think I finally have it down now, but I tend to get ions and isotopes mixed up, so a reminder is always helpful for me.) We made little diagrams using fwuffballs to represent the subatomic particles. We showed how an atom losing an electron could create charged particles, either positive or negative.

There are lots of fun things you can do with static electricity and a balloon. There's picking up tiny bits of paper, of course . . .

Or making a stream of water bend

Or sorting salt and pepper (if you get the balloon just the right distance away, the lighter pepper jumps up to the balloon while the heavier salt remains on the plate).

You can repel a piece of tape with another (rubbed) piece of tape

But maybe our favorite thing is just making people's hair stand up!

Also, here's a nice video of a lightning strike.

And here is a fun video showing how to light up a fluorescent bulb with static electricity.