5 ms·

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

271 points by alvivar 15y ago

jakeonthemove 15y 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...
- etherealG 15y ago
  future tech of awesomeness. loving it!
- etherealG 15y ago
  did you see the speculation about recreating the effect but horizontally instead of vertically? you could effectively have an invisible platform!
  - jackgavigan 15y ago
    did you see the speculation about recreating the effect but horizontally instead of vertically? you could effectively have an invisible trampoline! Corrected that for you. ;-)
tectonic 15y ago
I remember http://amasci.com/ http://amasci.com/ from over 10 years ago. A fun website. The hand-drawn holograms, for example, are great.
tawm 15y ago
So this is the kind of thing that's going to make our hovercars hover?
- joezydeco 15y ago
  Sure. All you need is a 20-foot wide sheet of poly film moving 20 feet up,over,and down at 1000 feet per second.
- bitwize 15y ago
  No, this is how the Combine built those force fields that Gordon Freeman can't get through.
- almost_usual 15y ago
  Probably would have better luck with super conductors
seats 15y ago
15 year old discussion, unfortunately. Makes it pretty likely this didn't stand up to scrutiny.
- wbeaty 15y ago
  Reasoning based on zero information? Heh. We could say "Pretty likely it was declared National Security and hushed up." Or we could say "Pretty likely that D. Swenson installed electrodes to quench the effect ...which task he was called in to perform." And Murphy's Law for experimental replication is that the desired phenomenon refuses to emerge except under identical conditions using only the original equipment.
- michael_dorfman 15y ago
  Could the OP please add [1996] to the title?
yread 15y ago
There is some more info from David Swenson: http://boards.straightdope.com/sdmb/showpost.php?s=b06561cd9b21d94322e22d4b0705566f&p=4212704&postcount=22 http://boards.straightdope.com/sdmb/showpost.php?s=b06561cd9... key quote: > 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.
- viraptor 15y ago
  From the article: "He could lean all his weight forward but was unable to pass." With that one, I imagine if his shoes were stuck to the ground, he'd just fall down, or at least noticed the resistance came from the shoes rather than body.
cfontes 15y 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...
- rbanffy 15y ago
  We don't know that nobody is trying to replicate it. We can only be sure nobody found a commercial application for it.
- forgottenpaswrd 15y ago
  "why isn't anybody trying to replicate and sell this ?" Because it can kill you, that's it. Electrostatic motors(capacitive) are older than electromagnetic(inductive), but using way more voltage than current means touching it will kill you. A lot of people have died from industrial plastic bags electrostatic charge with friction, so it now uses wire to ground it.
  - einhverfr 15y ago
    My understanding, albeit somewhat limited, is that generally amperes are a larger issue than volts in determining what sorts of electricity is dangerous. (Low voltage high amp circuits can't initiate sufficient amperage through the body to be dangerous in this way due to ohm's law but could still kill you through other means, such as burning you, but high voltage, low amp circuits are far less dangerous.) What am I missing?
    - wbeaty 15y ago
      Cap discharge? One story was the Robert VandeGraaff got the idea for his generator from a Boston printing plant, where the metal body of an ungrounded newspaper press on a wooden floor would give dangerous shocks to anyone approaching closely. If a machine is many meters across, and charges itself up to many tens of KV, the body capacitance may store lethal (joules) level of energy, e.g. 50KV at 1000pF.
ifewalter 15y ago
selling tickets might be nice....how i love product managers (even better sales managers) :)
Hacktivist 15y ago
Here is some more information on the phenomenon that causes this http://en.wikipedia.org/wiki/Triboluminescence http://en.wikipedia.org/wiki/Triboluminescence The most interesting section is how UCLA researchers created such powerful results that they were able to x-ray fingers. http://www.npr.org/templates/story/story.php?storyId=96139621 http://www.npr.org/templates/story/story.php?storyId=9613962... There are also a couple of videos on Youtube that show the effect in action.
- yread 15y ago
  Are you sure? There is no light involved
  - fleitz 15y ago
    Photons mediate the electromagnetic force it's very likely there was light involved.
  - ars 15y ago
    If there are sparks there is light. A spark is a very wide band transmitter - it creates just about every single frequency of light possible. See http://en.wikipedia.org/wiki/Spark_gap_transmitter http://en.wikipedia.org/wiki/Spark_gap_transmitter
  - Hacktivist 15y ago
    I guess I shouldn't have used such a strong word like "causes this" since the article was more about the force field and not the source of the ionized air. The point is that if the tape spool can create such a strong field then there is more than likely a visible light being created at the interface of the spool and tape caused by the charged atmospheric nitrogen which releases a photon when leaving the excited state.
- Qz 15y ago
  Is this the same kind of light you can make from the static electricity in say a polyester blanket on the couch?
goombastic 15y ago
If this effect were real, this would be ideal for scramjets and re-entry vehicles to reduce friction related heat.
- rbanffy 15y ago
  Wouldn't reducing friction also reduce the braking effect and make the spacecraft hit the ground at high speeds?
- aperiodic 15y ago
  Contrary to popular belief, the reason that spacecraft heat up upon re-entry is gas compression, not friction (remember the ideal gas law, PV = nRT). The gas would still be compressed by the electrostatic barrier, so the heating would still occur.
  - CamperBob 15y ago
    Is there really a difference between heat generated by friction and heat generated by gas compression, at the end of the day?
    - ars 15y ago
      Of course. They work very differently. If you have heat from friction you expect the heat along the length of the ship. If you have heat from compression you expect it at any point where the ship is not parallel to the air - but not along the length of it. Heat from friction can be aided by a low friction surface material. Heat from compression can be aided by not having any surface very perpendicular to the air (spread out the change in angle over a distance). With heat from friction you want a short ship - so just have the angled surface and be done with it. Heat from compression would benefit from a longer ship so you have space to gradually change the angle of a surface.
      - CamperBob 15y ago
        If you have heat from friction you expect the heat along the length of the ship. How in the world does that follow? Heat from friction will be generated in proportion to cos(angle) between the airflow and the surface at any given point, just like heat from compression would. It will flow along the ship's surface and soak into its interior volume just as if it were generated by compression.
cantbecool 15y 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.
viraptor 15y 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 ;)
- viraptor 15y ago
  And I was too late, already submitted: http://community.discovery.com/eve/forums/a/tpc/f/9701967776/m/20419888901 http://community.discovery.com/eve/forums/a/tpc/f/9701967776...
ChuckMcM 15y 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. 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. 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. 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.
- CamperBob 15y ago
  I bought a fairly large (750 KV) VDG kit on eBay a couple of years ago just for the lulz, and I soon came to appreciate how unpredictable and unintuitive electrostatic phenomena can really be. Not only was the charge-transfer mechanism between the belt, rollers, and brushes completely different from what I'd always assumed, but the macro-level effects were sometimes downright confusing. In some ways, the operation of a Van de Graaff generator is even harder to internalize than that of a Tesla coil. I expected longer discharges in dry weather -- nope, it does better in moderate humidity. I expected styrofoam peanuts to be consistently attracted (or maybe repelled) when thrown at the sphere, not to be attracted at first and then rapidly repelled at some small distance from the sphere. I expected the strongest discharges to occur when the generator was operated with no large objects nearby; instead, positioning it within a few feet of a tall wooden bookcase results in sparks (in any direction) at least 25% longer. So I'm not too surprised at tales of strange force fields in a cellophane-tape factory. I am surprised that the rollers didn't have grounding brushes all over the place... but given my experiences with the VDG, for all I know that would have made things worse.
jeggers5 15y ago
This happens because of this: http://en.wikipedia.org/wiki/Coulomb%27s_law http://en.wikipedia.org/wiki/Coulomb%27s_law. Mythbusters should definitely try this!
unabridged 15y 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?
astangl 15y 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.
- jff 15y ago
  Ok, this magnetron-on-lawnmower thing is interesting me. The problem I'm seeing is that unless you run an extension cord to the mower, it's not actually going to do anything. Steam is a useful way to turn pure heat into something that can push a piston, but turning water into steam doesn't actually generate any new power. I think it would be really cool to do... but the end result would surely be no better than simply putting an electric motor into your lawnmower. Also, this definitely reminds me of all those "free energy/orgone/powah of da pyramids" kind of things that people without a decent physics education get suckered into. Run your car on water!

271 points by alvivar 15y 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...

etherealG 15y ago
future tech of awesomeness. loving it!
etherealG 15y ago
did you see the speculation about recreating the effect but horizontally instead of vertically? you could effectively have an invisible platform!
- jackgavigan 15y ago
  did you see the speculation about recreating the effect but horizontally instead of vertically? you could effectively have an invisible trampoline! Corrected that for you. ;-)

tectonic 15y ago

I remember http://amasci.com/ http://amasci.com/ from over 10 years ago. A fun website. The hand-drawn holograms, for example, are great.

tawm 15y ago

So this is the kind of thing that's going to make our hovercars hover?

joezydeco 15y ago
Sure. All you need is a 20-foot wide sheet of poly film moving 20 feet up,over,and down at 1000 feet per second.
bitwize 15y ago
No, this is how the Combine built those force fields that Gordon Freeman can't get through.
almost_usual 15y ago
Probably would have better luck with super conductors

seats 15y ago

15 year old discussion, unfortunately. Makes it pretty likely this didn't stand up to scrutiny.

wbeaty 15y ago
Reasoning based on zero information? Heh. We could say "Pretty likely it was declared National Security and hushed up." Or we could say "Pretty likely that D. Swenson installed electrodes to quench the effect ...which task he was called in to perform." And Murphy's Law for experimental replication is that the desired phenomenon refuses to emerge except under identical conditions using only the original equipment.
michael_dorfman 15y ago
Could the OP please add [1996] to the title?

yread 15y ago

There is some more info from David Swenson: http://boards.straightdope.com/sdmb/showpost.php?s=b06561cd9b21d94322e22d4b0705566f&p=4212704&postcount=22 http://boards.straightdope.com/sdmb/showpost.php?s=b06561cd9... key quote: > 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.

viraptor 15y ago
From the article: "He could lean all his weight forward but was unable to pass." With that one, I imagine if his shoes were stuck to the ground, he'd just fall down, or at least noticed the resistance came from the shoes rather than body.

cfontes 15y 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...

rbanffy 15y ago
We don't know that nobody is trying to replicate it. We can only be sure nobody found a commercial application for it.
forgottenpaswrd 15y ago
"why isn't anybody trying to replicate and sell this ?" Because it can kill you, that's it. Electrostatic motors(capacitive) are older than electromagnetic(inductive), but using way more voltage than current means touching it will kill you. A lot of people have died from industrial plastic bags electrostatic charge with friction, so it now uses wire to ground it.
- einhverfr 15y ago
  My understanding, albeit somewhat limited, is that generally amperes are a larger issue than volts in determining what sorts of electricity is dangerous. (Low voltage high amp circuits can't initiate sufficient amperage through the body to be dangerous in this way due to ohm's law but could still kill you through other means, such as burning you, but high voltage, low amp circuits are far less dangerous.) What am I missing?
  - wbeaty 15y ago
    Cap discharge? One story was the Robert VandeGraaff got the idea for his generator from a Boston printing plant, where the metal body of an ungrounded newspaper press on a wooden floor would give dangerous shocks to anyone approaching closely. If a machine is many meters across, and charges itself up to many tens of KV, the body capacitance may store lethal (joules) level of energy, e.g. 50KV at 1000pF.

ifewalter 15y ago

selling tickets might be nice....how i love product managers (even better sales managers) :)

Hacktivist 15y ago

Here is some more information on the phenomenon that causes this http://en.wikipedia.org/wiki/Triboluminescence http://en.wikipedia.org/wiki/Triboluminescence The most interesting section is how UCLA researchers created such powerful results that they were able to x-ray fingers. http://www.npr.org/templates/story/story.php?storyId=96139621 http://www.npr.org/templates/story/story.php?storyId=9613962... There are also a couple of videos on Youtube that show the effect in action.

yread 15y ago
Are you sure? There is no light involved
- fleitz 15y ago
  Photons mediate the electromagnetic force it's very likely there was light involved.
- ars 15y ago
  If there are sparks there is light. A spark is a very wide band transmitter - it creates just about every single frequency of light possible. See http://en.wikipedia.org/wiki/Spark_gap_transmitter http://en.wikipedia.org/wiki/Spark_gap_transmitter
- Hacktivist 15y ago
  I guess I shouldn't have used such a strong word like "causes this" since the article was more about the force field and not the source of the ionized air. The point is that if the tape spool can create such a strong field then there is more than likely a visible light being created at the interface of the spool and tape caused by the charged atmospheric nitrogen which releases a photon when leaving the excited state.
Qz 15y ago
Is this the same kind of light you can make from the static electricity in say a polyester blanket on the couch?

goombastic 15y ago

If this effect were real, this would be ideal for scramjets and re-entry vehicles to reduce friction related heat.

rbanffy 15y ago
Wouldn't reducing friction also reduce the braking effect and make the spacecraft hit the ground at high speeds?
aperiodic 15y ago
Contrary to popular belief, the reason that spacecraft heat up upon re-entry is gas compression, not friction (remember the ideal gas law, PV = nRT). The gas would still be compressed by the electrostatic barrier, so the heating would still occur.
- CamperBob 15y ago
  Is there really a difference between heat generated by friction and heat generated by gas compression, at the end of the day?
  - ars 15y ago
    Of course. They work very differently. If you have heat from friction you expect the heat along the length of the ship. If you have heat from compression you expect it at any point where the ship is not parallel to the air - but not along the length of it. Heat from friction can be aided by a low friction surface material. Heat from compression can be aided by not having any surface very perpendicular to the air (spread out the change in angle over a distance). With heat from friction you want a short ship - so just have the angled surface and be done with it. Heat from compression would benefit from a longer ship so you have space to gradually change the angle of a surface.
    - CamperBob 15y ago
      If you have heat from friction you expect the heat along the length of the ship. How in the world does that follow? Heat from friction will be generated in proportion to cos(angle) between the airflow and the surface at any given point, just like heat from compression would. It will flow along the ship's surface and soak into its interior volume just as if it were generated by compression.

cantbecool 15y 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.

viraptor 15y 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 ;)

viraptor 15y ago
And I was too late, already submitted: http://community.discovery.com/eve/forums/a/tpc/f/9701967776/m/20419888901 http://community.discovery.com/eve/forums/a/tpc/f/9701967776...

ChuckMcM 15y 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. 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. 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. 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.

CamperBob 15y ago
I bought a fairly large (750 KV) VDG kit on eBay a couple of years ago just for the lulz, and I soon came to appreciate how unpredictable and unintuitive electrostatic phenomena can really be. Not only was the charge-transfer mechanism between the belt, rollers, and brushes completely different from what I'd always assumed, but the macro-level effects were sometimes downright confusing. In some ways, the operation of a Van de Graaff generator is even harder to internalize than that of a Tesla coil. I expected longer discharges in dry weather -- nope, it does better in moderate humidity. I expected styrofoam peanuts to be consistently attracted (or maybe repelled) when thrown at the sphere, not to be attracted at first and then rapidly repelled at some small distance from the sphere. I expected the strongest discharges to occur when the generator was operated with no large objects nearby; instead, positioning it within a few feet of a tall wooden bookcase results in sparks (in any direction) at least 25% longer. So I'm not too surprised at tales of strange force fields in a cellophane-tape factory. I am surprised that the rollers didn't have grounding brushes all over the place... but given my experiences with the VDG, for all I know that would have made things worse.

jeggers5 15y ago

This happens because of this: http://en.wikipedia.org/wiki/Coulomb%27s_law http://en.wikipedia.org/wiki/Coulomb%27s_law. Mythbusters should definitely try this!

unabridged 15y 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?

astangl 15y 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.

jff 15y ago
Ok, this magnetron-on-lawnmower thing is interesting me. The problem I'm seeing is that unless you run an extension cord to the mower, it's not actually going to do anything. Steam is a useful way to turn pure heat into something that can push a piston, but turning water into steam doesn't actually generate any new power. I think it would be really cool to do... but the end result would surely be no better than simply putting an electric motor into your lawnmower. Also, this definitely reminds me of all those "free energy/orgone/powah of da pyramids" kind of things that people without a decent physics education get suckered into. Run your car on water!