• KM Dailey

14 Van de Graaff Generator

Updated: Mar 5

I made a list of 100 things I should do that scare me. In 2020, I plan to complete all 100.

A van de Graaff generator builds up a huge amount of electric charge on a dome. You might know it as “the thing that makes your hair stand on end when you touch it.”

It’s a great demonstrator for electric fields, electrostatic charge, and electric potential. If you know how to use it right, and you’re careful to give very clear instructions, it’s perfectly safe. If you miss something, it’s still more or less safe—it’ll shock you, but it’s not going to kill or damage you. It’s just going to hurt.

For my first couple of years of teaching, I didn’t use the thing. It made me nervous. My teaching mentor told me, in very gentle and tactful terms, that I should probably suck it up (it was more like, “That one is a GOOD demo” in a sort of no-nonsense tone).

So I have to do it. And I do, every year. But it makes me nervous, especially when the kids ask me to be the one to touch the dome, because I know how to avoid shocking the students, but they don’t always know how to avoid shocking me. My first year, I got shocked six times in one day. Twice badly enough to make me shout.

No shocks for the first two class periods, though I did get a pretty nasty one for the last one, after my teaching mentor cleaned off the dome so it worked more effectively (but I didn’t think about it, so I kept turning up the knob too high).

I called this a level 2 fear, and I’ll leave it at that—it was more like level 1 for the first two class periods and level 3 for the last one, when the charge leaked into the air so strongly I could feel it in my hair and skin.

I don't love the fear, but I still love doing this demonstration. It's so worth it.

They did make me touch the dome. I don’t love that, but let’s be honest, my hair is just way too perfect for this demo (though the image above is actually from a couple of years ago).



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