Subdivision:

An exciting demonstration of subdivision.

Fine powders are dangerous because they have so much surface area exposed to the air when they are airborne. I remind you of coalmine coal dust explosions. Here is a memorable demonstration device that safely shows what this means.

Attach a rubber hose to a connection that has been fitted into a empty paint can. Inside the can fix a candle upright. Attach a funnel to the fixture with a short hose on the inside of the can. Place cornstarch in the funnel. Light the candle and close the lid onto the paint can.

Blow into the rubber hose outside the can. The cornstarch will become airborne on the inside and the candle will ignite it. The lid will fly from the can. Use Caution !!! goggles !!! Try it in a hood first etc.

Your students won't forget this one !!!

Paintcan with hose and fixture so that air from the hose can enter the can.

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Inside of can. Note the cornstarch in the funnel and the candle ready to be lit.