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.