Adapted from Kathryn Nelson
(See Activity References)
Materials: 2 matches
Glass medicine bottle
Procedure: Put the two matches inside the glass medicine bottle. Wet the stopper and put it on the bottle, but not tight. Place the bottle in the sun and hold a magnifying glass to the bottle, so that the sunlight is focused on the match tips. The sunlight should light the matches. The flame will send the stopper flying out of the bottle. It will make a loud pop as it comes out of the bottle. Perform this experiment outside and make sure no one is standing close enough to get hit by the stopper as it pops out.
Explanation: The burning matches represent the burning gases in the engine and the magnifying glass represents the effect of the spark plug through the ignition.