Water flow in salt solutions contemporary exposed to an electrical and constant magnetic field When a permanent magnet is held motionless close to a salt solution which already has been exposed to an electrical field a flow in the water will be induced and can be detected by applying some grains. I would explain this phenomenon as a consequence of a force pushing the moving ions perpendicular to their original direction between the electical poles. So moving ions in water seem to be able to interact with the water molecules and move them. But the motion of ions occured already before the magnet was applied. Why is it so that only the deflection of ionic movement results in a detectable water motion? 
I would be very satisfied if I would be able to come up with a streight forward explanation to my young students. 
 A: The critical observation here is that before the magnet is introduced, there are equal numbers of oppositely charged ions moving in opposite directions, exerting no net force on the water around them.  The magnet, however, will deflect a positive ion going one way in the same direction as it will deflect a negative ion going the other way.  This produces a net flow of ions in the direction of the deflection, and thus a net force on the water.
A: 
But the motion of ions occurred already before the magnet was applied. Why is it so that only the deflection of ionic movement results in a detectable water motion?

A saline solution in the presence of only an electrical field will undergo charge separation. The charges move oppositely to each other since the force on them initially is
$$q\vec{E_{ext}}$$
and $q$ changes signs for the two species. Since the motion of the two ionic species are equal$^1$ & opposite, so is the force imparted by this drift to the solution medium and hence no motion occurs. After a while the charge separation induced generates its own opposite electric field that cancels the external field - thus the solution reaches equilibrium and no more average drift occurs.
In the additional presence of a crossed magnetic field $\vec{B_{ext}}$, the initial force on the charges, becomes
$$q(\vec E_{ext}+\vec v \times\vec B)$$
While the electric component of the force still accelerates the charges in opposite direction, the magnetic force is in the same direction for both positive and negative charges. Not only that it deflects them orthogonally to their electric motion. This  allows for the drifting charges to successfully impart a net momentum to the solution medium while extracting energy from the electric field.

$^1$ Depending on the differences of interaction of the two ionic species with the same solution medium, the motion imparted to the solution medium may not be exactly same. In such cases during this time, a solution movement may be observed.
A: The electron was the number of electron which has number of charge is $1.6\cdot10^{-18}\,$eV. As the electric field is the region in which charged particles experience the force to perpendicular direction between electrical poles.The moving ions consists of positive charge and negative charge therefore the cations and anions which can be moving ions in original direction between electrical poles.Thus,the electromagnetism concept should be use the electrodes to be electromagnet being wrapped round the electrodes by copper wire as the resistance lower, the current must be increase to be magnetized.
