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"Invisible Electrostatic Wall" at 3M adhesive tape plant (1996)

271 pointsby alvivarover 13 years ago

15 comments

ChuckMcMover 13 years ago
We did this experiment in physics back in college. If you get sufficient charge you repelled by charge of the same polarity. I would speculate that the charge on people was the same as the charge being created in the spooling area (it is a giant Van DeGraff generator type apparatus after all). That would also correlate with the humidity component as the humid air would have a lower dielectric effect and you would get a lower max charge due to leakage into the surrounding environment.<p>The edge of that electric field would feel to you exactly like you were a magnet of the same pole trying to move into it.<p>Per some other comments here the biggest risk would no doubt be creating a conductive path for the charge to dissipate. At those levels it can and does ionize air and create lightning.<p>Would be great to get a picture of the factory setup. I bet you could trace the charge sources. In physics 101 we had to compute how much charge you would have to have on your body to levitate off the ground. It was a lot less then you might imagine, the challenge of course was keeping it on your body and not zapping things nearby in the occasional ionizing discharge. I was busily thinking up high K clothing concepts for a while to try to solve that issue but alas, nothing came of it.
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yreadover 13 years ago
There is some more info from David Swenson:<p><a href="http://boards.straightdope.com/sdmb/showpost.php?s=b06561cd9b21d94322e22d4b0705566f&#38;p=4212704&#38;postcount=22" rel="nofollow">http://boards.straightdope.com/sdmb/showpost.php?s=b06561cd9...</a><p>key quote:<p>&#62; I think the best explanation has to do with the film being at or vaery near the theoretical charge density limit and just the right combination of resistance between the person and floor. With the electric field at its maximum at the center of the tent formed by the film, the conductive body (person) approaching the center was actually pinned to the floor. Had the floor been more conductive, the person would have been closer to ground and probably would have received a massive shock from a propagating brush discharge. But being isolated from ground, no charge separation occured resulting in the electrostatic "pinning" effect.
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seatsover 13 years ago
15 year old discussion, unfortunately. Makes it pretty likely this didn't stand up to scrutiny.
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viraptorover 13 years ago
It's time to look for MythBusters suggestions email, I guess... If anyone has a budget to replicate that setup as a one-time funny activity, it's going to be them ;)
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jakeonthemoveover 13 years ago
Isn't this "invisible wall" basically a force field like they show on various Sci-Fi shows? Can it be replicated and used on a spacecraft to protect it from radiation and more importantly, small meteorites? That would be really cool...
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cfontesover 13 years ago
Ah Ok, why isn't anybody trying to replicate and sell this ? it would be worth more than gold, and it's sitting there in an old maillist ? come on...
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Hacktivistover 13 years ago
Here is some more information on the phenomenon that causes this<p><a href="http://en.wikipedia.org/wiki/Triboluminescence" rel="nofollow">http://en.wikipedia.org/wiki/Triboluminescence</a><p>The most interesting section is how UCLA researchers created such powerful results that they were able to x-ray fingers.<p><a href="http://www.npr.org/templates/story/story.php?storyId=96139621" rel="nofollow">http://www.npr.org/templates/story/story.php?storyId=9613962...</a><p>There are also a couple of videos on Youtube that show the effect in action.
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jeggers5over 13 years ago
This happens because of this: <a href="http://en.wikipedia.org/wiki/Coulomb%27s_law" rel="nofollow">http://en.wikipedia.org/wiki/Coulomb%27s_law</a>.<p>Mythbusters should definitely try this!
tectonicover 13 years ago
I remember <a href="http://amasci.com/" rel="nofollow">http://amasci.com/</a> from over 10 years ago. A fun website. The hand-drawn holograms, for example, are great.
unabridgedover 13 years ago
If this actually happened, don't you think 3M engineers would be aware of the effect before it was making a wall the size of a room that could stop a human? They didn't notice small parts and dust being repelled? And they couldn't capitalize on it even just by making a small public display of hovering objects?
astanglover 13 years ago
This is one of a couple tantalizing stories I've seen on that site over the years, something that sounds really promising but then leads nowhere, calling the whole story into question. The other one is the lawnmower engine retrofitted with a magnetron in place of the spark plug, turning the engine into a type of steam engine running on water. Poster acted like it was no big deal, and apparently moved on to more interesting things.
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goombasticover 13 years ago
If this effect were real, this would be ideal for scramjets and re-entry vehicles to reduce friction related heat.
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cantbecoolover 13 years ago
I wish smart phones were prevalent back in 96'. It would have been fascinating to view a video of the phenomenon described in this story, but I probably would have been skeptical thinking it was simply special effects.
tawmover 13 years ago
So this is the kind of thing that's going to make our hovercars hover?
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ifewalterover 13 years ago
selling tickets might be nice....how i love product managers (even better sales managers) :)