Guillotine: Eddy Current Braking, 5K20.20

Location: Floor Item Room 2237.

Description:

The large copper blade of the Guillotine is released from a height of 7 feet 10 inches. Strong magnets are placed about a foot above the chopping block. These magnets are strong enough to slow the blade to almost a stop with induced eddy currents within the copper blade.

The Guillotine with base is 10' 4" tall, 15.5" wide, and 1.5" thick. The base is 23" x 23" x 28".

The blade is 1/4" thick and is 12" by 11.75" on long side and 12" by 9.75" on the short side. It is pure copper and its weight is 818.5 grams.

The Magnets: The bar of magnets are very strong and came from an very old computer hard drive. We got them for about $20 each from American Science Surplus many years ago. They have magnetic field strength of about 4.5 Kilogauss at the surface, about 3.0 Kilogauss one quarter inch away, and 2.5 Kilogauss on the other side of the copper blade, about 3/8 of an inch from the surface. The average magnetic field strength within the 1/4 inch thick copper blade is about 2.75 Kilogauss. The blue parts are the North Poles and the Red are the South Poles.

Important Setup Notes:

1. Bring in some vegetables (Carrots, Zucchini, Cucumber work well) to chop

Setup:

1. A screwdriver is needed to fasten the upper part of the Guillotine to its base.
2. Make sure the cord for the blade is untangled.
3. Test the blade release.

Cautions, Warnings, or Safety Concerns:

1. The blade is NOT sharp but is beveled.
2. Blade WILL cause bodily harm (without the magnets).
3. Keep all body parts out of the way of the blade once the blade is lifted out of its holder.
4. The magnets are strong enough to wipe out credit cards.
5. Demonstration may require practice.

References:

1. Wikipedia

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