Magnet races

HOW

1. Select a tube and move the magnet on it to the position at the top.
2. Release the magnet and observe its movement.
3. Conduct the experiment using other tubes and compare the effect.
4. Rotate the frame with the tubes so that all magnets are in the upper position simultaneously. Watch the magnets race.

WHY

The falling magnet induces eddy currents in the tube. They are the source of the magnetic field that opposes the field of the magnet. This makes its movement slower than if it was falling freely.

The slowdown effect increases with the intensity of the eddy currents. This magnitude, in turn, depends on the electrical conductivity of the tube. The materials used in the model are, in turn, copper, aluminium, brass and stainless steel.