Transcript Ivan Lomachenkov
The electromagnetic rotation of
The rotation of water in magnetic and
electrical fields demonstrates the
effect of a magnetic force on charged
particles. It’s a simple equipment.
• cylindrical glass vessel (about 10-15 cm
• two electrodes (central and circular
• magnet (preferably a cylinder);
• source of electricity (about 10-15 V);
• ampere meter, voltmeter;
The physical picture:
• Put some salt into the water (either NaCl or
CuSO4), about 5-10%. Therefore we have the
H2O + NaCl=>Na+ + ClThe positive and negative ions begin to move in
the radial direction but the magnetic force acts
perpendicular to the ion’s trajectory. Hence the
water starts to rotate.
The scheme of the facility:
• It is not difficult to estimate the radial velocity of
the ions of Na. The result is vr~ I/n, where I is
the current and n is the concentration of the ions.
For a current ~ 0.1 A we have vr~ 10-7m/s.
• We can also estimate the circular component of
the velocity: v~ nvrB/, where - the viscosity
of the solution. For inductance B~10-2 T and
~10-3kg/(m·s) the result is v ~ 10-2 m/s.
• A visible observation confirms this estimation.