Short Magneto Hydro Dynamics demo

Quick demo of MHD.

Two bowls containing a saline solution.
One bowl suits over a strong magnet. The other does not.
Some dill is floating in each solution.

A pair of copper electrodes connected to a 9V battery is introduced first to the non-magnet solution. Result: A little bit of hydrolysis evident at the cathode (hydrogen) and anode (chlorine). No motion of the dill.

The electrodes are moved to the solution sitting atop the neodymium magnet, close to the dill. Result: Dill moves through the electrodes. Some hydrolysis also.
This motion is caused by Magneto Hydro Dyamics (or MHD for short).
The saline solution allows for current to flow from one electrode to the other. Conventionally, positive current is from the positive to the negative electrode. The magnetic field lines are pointing up through the bottom of the glass bowl. Positive is from North to South by convention.

The fluid experiences a force orthogonal to the magetic and electric fields. You can work out which direction using the right hand rule where your forefinger points in the direction of positive current, your middle finger points in the direction of positive magnetic field and your thumb indicates the direction of the force the fluid experiences.

This is like an electric motor in liquid form.