PURPOSE: To blast a cola 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.
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) The plasma "theta pinch" phenomenon occurs when the capacitor is discharged. This effect causes radiation pressure on the can which breaks it in two and blasts apart the two halves.
This is an UNFORGETTABLE DEMONSTRATION. A must when you cover electromagnetism.
SUGGESTIONS: This device is DANGEROUS. You must obtain permission from a Lecture-Demonstration staff member before attempting to operate it by yourself.
REFERENCES: (PIRA 5K10.90) See Demonstration Reference File for a very nice article by Prof. Alan DeSilva of the University of Maryland Plasma Physics research area, who designed this device and describes its theory.
EQUIPMENT: Electromagnetic can crusher.
SETUP TIME: None, if you know how to operate it.
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