|DCS# 5K20.25||NWU# E-60||Location: under catwalk|
|title: Magnetic Tube Drop|
aka: Eddie Current Braking / Cow Magnet Drop
An aluminium tube down which blue cylinders can be dropped. The non-magnetic one falls freely and takes little time to fall. The other is a pile of ring magnets (a cow magnet: used to trap ferrous materials in the first stomach of a cow to prevent ingestion injuries.) with a strong magnetic field that produces eddie currents in the alumium tube and has a very long time of fall. Small rare earth magnets will also work well.
There is a magnetic indicator material attached to the tube to show the passage of the magnet.
The velcro on the end of the tube is for attachment to a scale to show the different weights of the device as the magnet descends and then falls out.
A camera pointed down the tube will show the magnet being repelled from the walls.
Why do eddie currents produce such a slow terminal velocity?
What would happen if the aluminum tube had less resistance to current flow?