Chemical Concept Demonstrated: The relationship between the rate of a reaction and the surface area available for the reaction
|The dust-can explosion apparatus consists of:
Light the candle, replace the lid, and squeeze the bulb several times to eject the dust in the can.
When the bulb is squeezed, flames shoot out of the top of the can. This can be repeated several times.
When the bulb is squeezed, the powder in the funnel is dispersed into the air. As the powder touches the candle, it ignites. The entirety of the airborne powder catches on fire. However, the powder that is still in the funnel is unaffected, as it can be shown that more such bursts of flame can be produced.
The powder still in the funnel has less surface area than the dispersed powder. The airborne powder catches on fire, but the funnel powder does not. As an alternate method, one could simply place a sample of lycopodium powder on an asbestos pad, hold burner to it in this "compact" state, then initiate the dust can explosion.