| MadSci Network: Engineering |
Assuming that you can get past any design difficulties associated with using a liquid as a conducting medium, an electromagnet may be made with a fluid electrolyte. The real comparison to conventional electromagnets lies in the ability of each medium to carry current. Let's compare copper wire, which has a resistivity of 10-6 ohm-cm, to a great liquid electrolyte, 10-1 ohm-cm. These numbers by themselves demonstrate that, given a constant input voltage, by Ohm's law there will be 5 orders of magnitude difference in the currents that these two media can carry. What does this mean for magnetic fields? Let's take a solenoid, which is basically wire that is wound many times in a spiral; passing current through the wire induces a magnetic field. The field produced at the center of the solenoid is proportional to the current. A 100 turn-per-cm solenoid made from copper wire carrying 0.1 amperes generates a central field of 13 Gauss. The same solenoid made from our electrolyte would induce a field of 13x10-5 Gauss. As a reference, the magnetic field of Earth is around 0.5 Gauss. So, an electrolyte-electromagnet would generate a very small magnetic field even compared to that of the earth.
Try the links in the MadSci Library for more information on Engineering.