We had great fun with this in my neighborhood when I was, oh, fourteen years old
or so.
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Take a tennis ball can (we had metal ones in those days, but I suppose the new
plastic ones would work too, at least a few times).
-
Cut a small hole near the bottom of the can.
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Now pour some rubbing alcohol in the can. Not too much!
-
Drop a tennis ball in, take aim, then fire it by sticking a lighted match in the hole. The
tennis ball will easily fly thirty or forty feet in the air.
Sometimes it would
catch on fire and we would have to chase a
flaming tennis ball
across the neighbor's lawn. Be careful. It was safe enough with rubbing
alcohol, which is diluted isopropyl alcohol. Using anything stronger than
rubbing alcohol is asking to have your hand blown off.