small, cheap, effective explosions...
bijanv said:
does anyone know any cool small explosion or projectile (missile) type experiemnts?
"Watch Mr. Wizard," with Don Herbert, a tv program from probably 50 years ago, did a neat one... as with any and all explosive items, extreme care must be taken or you'll damage your body. i will accept no responsibility for any damage done to anybody by citing the following experiment...
take a dry, empty one-gallon paint can.
drill a hole, about 3/4" in the bottom, off-center, about 1/3 of the way across the diameter.
drop a small funnel, about 3" diameter into the hole.
attach a small rubber/plastic hose to the bottom of the funnel. you'll need to support the can so that the funnel can seat fully against the hole in the bottom and the bottom of the funnel and the hose are not in contact with anything under them.
put a few teaspoons of regular cooking flour into the top of the funnel.
cut a candle to about 2" long, straight across the bottom.
light the candle and put it into the can.
tap the top onto the paint can. firmly, but try to not hit the can in such a way to knock over the candle.
without inhaling first... blow into the tube attached to the funnel.
this will blow a cloud of flour into the can above the candle flame, the flame will ignite the combustible mixture, and the resulting heat and expansion will blow the top of the can at least 10-20 feet into the air.
it will probably not go straight up, so use a 10-20' long length of rubber/plastic tubing so that you're not too close to the can when it goes off, and you can duck and cover if it comes down towards you.
safety glasses and a bicycle helmet are probably some good things to use, here!
enjoy!