Can this be done?

[h4tt3n]

I was wondering if this experiment is physically possible...

 

Fill a small oblong container, like a plastic tube, with water.

 

Now place the filled tube in a high-voltage electric field, possibly created by a Van der Graaf generator, so that each end of the tube points at each electrode.

 

Since water is a highly polar liquid, this will cause all water-molecules to point in the same direction, trying to cancel out the electric field.

 

Now freeze the water and turn off the electric field.

 

What do we have? A rod carrying an eletric field without spending energy, just as an iron rod may carry a magnetic field?

 

 

best regards,

Michael

[insane_alien]

not really.there would be no measurably external field since the charge is still evenly dispersed throughout the ice.

[h4tt3n]

Hmmm... I don't get it.

 

Each water molecule carries a small electric field. If you turn multiple water molecules the same way, won't the fields add up the same way as in a magnet?

 

Michael

[ecoli]

Hmmm... I don't get it.

 

Each water molecule carries a small electric field. If you turn multiple water molecules the same way' date=' won't the fields add up the same way as in a magnet?

 

Michael[/quote']

 

i don't think so... they should cancel each other out.

[insane_alien]

magnetic fields and electric fields work differently although they are related. maybe a phyzorcist should answer this one.

[Cap'n Refsmmat]

Magnetic and electric fields are the same thing.

[Klaynos]

Magnetic and electric fields are the same thing.

 

yes and then again no....

 

There will be no magnetic filed as the charges are stationary.

 

So this is an electrostatic problem.

 

If we consider a guassian surface no matter which part of the rod it passes through (or it it encumpases the whole rod) the charge enclosed by the surface will always be 0 because the electic dipoles frozen would always be small enough to count as having 0 charge unless you are REALLY REALLY close to an individule molecule.

 

But there is something else we should consider in this problem. Freezing the water creates a bond which requires a certain setup of the molecules within the water, this would change the polarisation (probably destroy it iirc). And also as soon as we remove the E filed any dipole set up around each individule atom due to the E field would be removed unless you freez the water to 0K and then there's lots more fun stuff that comes into play, one factor is that this would be impossible :s

[h4tt3n]

There goes my perpetuum mobile

 

Thank you for explaining why it doesn't work. I can see it's a bit more complicated than I first imagined.

 

regards,

Michael