I f a have a coil with an electric current flowing through it, and I place it inside of a magnetic field, it will move.

Now my question is, what happens if I have a droplet of liquid with an electric current flowing through it, will it also move ? If not, why not ?


Yes, of course it will move. Here is a familiar science demonstration, the mercury 'beating heart' BEATING HEART which shows a crude battery circuit (the mercury and the iron in a mild acid). When the iron touches the mercury, the battery puts a current through the contact point, and that current deforms the mercury because it creates a changing magnetic field.

The deformation breaks the contact, and the force on the mercury goes away, which reestablishes electric contact... and it oscillates.

It's literally a changing magnetic field that's moving the mercury, but the coil-in-a-field causes more of a torque effect than a translational motion. The application of torque to a liquid is a difficult thing to demonstrate; how would one know that a liquid drop was rotating?

A drop of conductive liquid in a changing magnetic field WILL transformer-couple to that field, and generate a little loop of internal current. The problem, then, is to see a drop become nonspherical when a changing magnetic field excites it, and then see some indication of axial tilt due to a nonchanging magnetic field.

Probably, this could be accomplished, with stop-action video to record droplets in free fall. It'll look like a bunch of wires with a quivering raindrop falling through a magnet gap...

  • $\begingroup$ Thanks for your answer, but I don't see the relation between the mercerury beating heart and an applied magnetic field to a current passing through a liquid. The mercury beating heart is an electrochemical redox reaction. $\endgroup$ – henry Apr 5 '17 at 5:07
  • $\begingroup$ Oh, the beating heart is electromechanical. The force on the mercury is plain old magnetism; the 'redox reaction' doesn't apply force, just current that makes a crude electromagnet. $\endgroup$ – Whit3rd Apr 5 '17 at 5:51
  • $\begingroup$ Do you think, one could split the mercury with the magnetic force ? $\endgroup$ – henry Apr 5 '17 at 6:13
  • $\begingroup$ Yes, one can split the liquid; such force can be enough to explode a wire, or to shrink a coin (I have a US quarter that's about the diameter of a dime). $\endgroup$ – Whit3rd Apr 6 '17 at 4:17
  • $\begingroup$ Wow ! How did you do that ? ... and how exactley would you split the liquid ? $\endgroup$ – henry Apr 6 '17 at 10:43

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