TOPIC:

ID Code: K2-62
Purpose: Blasts a soda can into two pieces using electromagnetism
Description: A 400 microfarad capacitor is charged to 3000 volts (1.8 kilojoules) and discharged through a three-turn coil into which an aluminum soft drink can has been positioned. With the circular windows open, the two pieces of the can will be blasted over thirty feet to the sides of the large lecture hall. Charging the capacitor to less voltage results in a can with a "waist."

This device can be explained in two distinct ways:
(1) The rapidly rising current creates a rapidly rising magnetic field along the axis of the coil, which in turn induces an electric field going in circles inside the coil. The induced electric field causes an electron current in the can which experiences a vxB force in the magnetic field of the coil, causing the can to break into two pieces which are blown to the opposite sides of the lecture hall.
(2) A type of "theta pinch" phenomenon. Click this link for a little more information on this. Another way to understand this is that the induced current around the can is opposite to the current in the primary coil, since it is opposing the change in flux. These concentric opposite currents repel each other, so the can is pinched and torn apart and ejected out the sides.

This is an UNFORGETTABLE DEMONSTRATION. A must when you cover electromagnetism.

The web site hibp.ecse.rpi.edu/Can_Crusher/home.html contains a drawing and animation showing how the RPI electromagnetic can crusher works.

Availability: Available