Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Michael Ridgway on 17/06/2010 12:30:02

Title: Would an electrical current flowing through water create a magnetic field?
Post by: Michael Ridgway on 17/06/2010 12:30:02

Michael Ridgway asked the Naked Scientists:
   
I would like to know if an electic current through water would create a magnetic field?

To give an example, if you were to make a coil from a very thin plastic flexible tube containing salt water (that contucts electricity well) and you put this coil round an iron bar, would the iron bar become magnetic when you applied an electric charge to the coil, and if so, how  would the effect compare to say a copper wire - would the water coil be as efficient or much less efficient?

What do you think?

Title: Would an electrical current flowing through water create a magnetic field?
Post by: RD on 17/06/2010 12:41:18

Quote from: Michael Ridgway on 17/06/2010 12:30:02

I would like to know if an electic current through water would create a magnetic field?

Yes ... http://en.wikipedia.org/wiki/Magnetohydrodynamics

http://en.wikipedia.org/wiki/Magnetohydrodynamic_drive#Principle

Title: Would an electrical current flowing through water create a magnetic field?
Post by: Geezer on 17/06/2010 18:35:09

Quote from: Michael Ridgway on 17/06/2010 12:30:02

Michael Ridgway asked the Naked Scientists:
   
I would like to know if an electic current through water would create a magnetic field?

To give an example, if you were to make a coil from a very thin plastic flexible tube containing salt water (that contucts electricity well) and you put this coil round an iron bar, would the iron bar become magnetic when you applied an electric charge to the coil, and if so, how  would the effect compare to say a copper wire - would the water coil be as efficient or much less efficient?

What do you think?

I've never tried it, but I don't see why it would not work. Copper has a low resistance. The salt water will have much higher resistance, so a given current will produce a lot more heat than a copper conductor. If the current gets too great, the water will boil and probably destroy the tube.

I think copper would be a lot more efficient, and probably a lot safer!

Title: Would an electrical current flowing through water create a magnetic field?
Post by: samaste.march on 18/06/2010 07:22:11

I was tried this but can't get success ed. When copper has a low resistance, at that time salt water is higher resistance and lot more heat a copper conductor. If current is high voltage then the water will boil and it will destroy the tube.

Title: Would an electrical current flowing through water create a magnetic field?
Post by: krytie75 on 18/06/2010 16:19:04

An excellent question Michael!

What I think is more interesting though is the implication that conversely magnetic fields can be used to create an electric current in the salt-water solution.  According to the wiki article RD linked to it is possible, but the fluid must be flowing.

krytie75