Can this be done?

[GemmaD]

I came across these videos on YouTube of some guys doing crazy things with static electricity. Can any of these be done?

 

[swansont]

No, these are faked, in what looks to be just an excuse for some boys to rub each other with balloons. Strange fetish, that.

 

The first objection is that all of the target items are insulators, not conductors. There shouldn't be a spark. The second is that there isn't nearly enough energy to do what is being claimed.

 

This is reminiscent of the cell phones popping popcorn video from a while back, which I blogged about. Appying that to the popcorn "magic" here, and correcting the numbers from my post (I had an assumption that was off) — it takes tens of Joules of energy to pop a single kernel of popcorn.

 

The energy contained in a capacitor is 1/2 CV^2, and the human body has a capacitance of several hundred picofarads. Let's assume 2000 pf and a kiloVolt of potential difference. That's a milliJoule of energy, and it assumes a complete discharge, which only happens if the target is a grounded conductor.

 

With the 2000 pf capacitance, you'd need 100 kV of potential to get 10 Joules, perhaps popping a single kernel of popcorn. A 5mm spark requires about a 16 kV potential difference

 

edit to add: the original video is an ad, so consider that in the mix.

Edited June 26, 2009 by swansont