# What happens when an aqueous solution is exposed to an external electric field?

I know that when you use electrodes the ions flow to the corresponding electrons. But what happens if the solution is placed, say, in between the plates of a very powerful capacitor? Will the ions move to the ends of the container?

 Unknown008 Posts: 8,147, Reputation: 3745 Uber Member #2 Jul 5, 2012, 03:09 AM
I don't see why not. I believe it would be just like putting a neutral insulated metallic dome between electrodes (without touching) and charges just accumulate but there is no flow of charge from the dome to the electrodes.
 VishalManu Posts: 7, Reputation: 1 New Member #3 Jul 5, 2012, 03:19 AM
Yes i agree. So now if we place an insulator in between the container and turn the electric field off, will the ions attract each other? or in other words will the insulator experience a force??
 Unknown008 Posts: 8,147, Reputation: 3745 Uber Member #4 Jul 5, 2012, 03:22 AM
Going in that direction of thinking, the insulator will experience an equal force from both of its sides.

In this case, it would be like making two insulated domes touch each other, separate the charges using charged plates and then separating the two domes.
 VishalManu Posts: 7, Reputation: 1 New Member #5 Jul 5, 2012, 03:33 AM
Quote:
 Originally Posted by Unknown008 Going in that direction of thinking, the insulator will experience an equal force from both of its sides. In this case, it would be like making two insulated domes touch each other, separate the charges using charged plates and then separating the two domes.
I am sorry but I haven't been able to grasp the concept of the domes. I was wondering if the insulator would experience an increase in force? My actual concern is whether it is possible for the ions to handle a higher pressure. i.e, if the insulator were a dielectric gas is it possible for the ions to hold it in place?

Normally the air is dispersed mostly because of the pressure differences but if the ions can generate a high enough pressure through out the height will it be possible?
 Unknown008 Posts: 8,147, Reputation: 3745 Uber Member #6 Jul 5, 2012, 04:10 AM
I'm not sure what you mean by 'holding it in place'.

The force exerted by the solution would be equivalent to a case where you place a cardboard in a water tank. There is an equal force on both sides of the dielectric you would use, with the exception that the force would be a little higher due to the ions.

Maybe it would help if you said what you were trying to do?
 VishalManu Posts: 7, Reputation: 1 New Member #7 Jul 5, 2012, 04:23 AM
Quote:
 Originally Posted by Unknown008 I'm not sure what you mean by 'holding it in place'. The force exerted by the solution would be equivalent to a case where you place a cardboard in a water tank. There is an equal force on both sides of the dielectric you would use, with the exception that the force would be a little higher due to the ions. Maybe it would help if you said what you were trying to do?
Yes ok could u check the following link
http://www.hovertech.com/home/research/hydrostatic.html
I was just trying to understand the feasibilty of the above . I couldn't find any more info, so from whatever I could infer from the adjacent diagram, I thought maybe a thin aqueous layer of ions on both sides of the dielectric gas is able to hold the air pressure.
 Unknown008 Posts: 8,147, Reputation: 3745 Uber Member #8 Jul 5, 2012, 04:44 AM
I'm not sure I understand the principle they are trying to use in that project. "While no energy is consumed in levitating the craft" That part specifically just doesn't make any sense to me.

A hovercraft need to generate constant pressure so that it can stay airborne, and if you're using the principle of using the electrostatic force contained within the solution to do that I doubt it would be enough. The air pressure between the ions will expand due to the extra force suddenly generated, but once they go away by pushing up the hovercraft, the air gets back to its original pressure following PV = nRT. The volume cannot go indefinitely smaller...

Thus, you would need a constant supply of air which would keep the air from circulating between the 'skirt' of the hovercraft.

Well, unless I have been overlooking something, I don't think that this project can work.
 VishalManu Posts: 7, Reputation: 1 New Member #9 Jul 5, 2012, 08:15 PM
Quote:
 Originally Posted by Unknown008 I'm not sure I understand the principle they are trying to use in that project. "While no energy is consumed in levitating the craft" That part specifically just doesn't make any sense to me. A hovercraft need to generate constant pressure so that it can stay airborne, and if you're using the principle of using the electrostatic force contained within the solution to do that I doubt it would be enough. The air pressure between the ions will expand due to the extra force suddenly generated, but once they go away by pushing up the hovercraft, the air gets back to its original pressure following PV = nRT. The volume cannot go indefinitely smaller... Thus, you would need a constant supply of air which would keep the air from circulating between the 'skirt' of the hovercraft. Well, unless I have been overlooking something, I don't think that this project can work.
Yes I understand, it's an unlikely for it to work. I was just trying to understand the possibilities. What I am wondering is that... say we take a thick rectangular frame
and on both sides of the frame if we can somehow put ionic solutions will it prevent the air from escaping? (Much like 2 magnets can hold on to a cardboard)
Can it maintain the air tight seal?
If unsure I was hoping to verify this mathematically.
 Unknown008 Posts: 8,147, Reputation: 3745 Uber Member #10 Jul 6, 2012, 10:02 AM
I'm not sure how you are using the frame and ionic solutions to prevent the air from escaping...

If you could make a diagram, that would be really useful.

But if I understand well, you would prevent the air from escaping from under the hovercraft? Then, that means that the air pressure will rise under the hovercraft until the pressure in the reservoir of pressurized air equals that under the hovercraft, point at which, no air would move and the hovercraft settles down.

Something else though would be that you cannot prevent air escape in the first place, unless you seal the separation between the hovercraft and the ground, at which point, the above would occur.

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