Joey Green's Mad Scientist

Smoke Bomb

What You Need

1/4 cup sugar
3 ounces saltpetre (from a drugstore or medical supply store)
Bowl
Saucepan
Spoon
Paper cup
Wooden matches

What to Do
With adult supervision, combine the sugar and saltpetre in the bowl, then heat in the saucepan over very low heat, stirring constantly, until the mixture melts into a plastic substance that resembles caramel. Remove from the heat, poor into the paper cup, embed a few wooden matches, heads up, into the hardening substance, and let cool.
When the smoke bomb cools and hardens, peel off the paper cup, place the smoke bomb inside a clean, empty tin can or on a concrete surface (away from flammable objects or areas), light the match heads, and stand back. (Or you can simply leave the paper cup in place and light it on fire.)

What Happens
The smoke bomb produces enough thick white smoke to fill a public restroom.

Why It Works
The melted sugar becomes a candy that encapsulates the saltpetre, making it easier to ignite.

Bizarre Facts

In ancient Chinese kitchens, saltpetre was commonly used as a preserving and pickling salt.
Saltpetre is one of the three original ingredients in fireworks.
Smoke is simply small particles made airborne by the buoyancy of the hot gases produced by combustion.
Along the Great Wall of China, guards sent smoke signals made with wolf dung, because the smoke hung in the air for a long time.
In the movie October Sky, the rocket boys mix saltpetre and sugar to make rocket fuel.

The Joys of Saltpetre
Saltpetre, known to chemists as potassium nitrate, is commonly believed to reduce a man's primitive urges. It doesn't.

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