what are the specs to making a fog ball cannon from a rubbish bin, fog machine rubber band and garbage bag?

hey, a while ago in high school out teacher was showing uss tuff to do with the transferance of energy and stuff like that, what he brought into class one day was a rubbish bin, with a hole cut out bottom, and on the lid, there was a rubbish bag(the big black ones) , on top with a rubber band taped to it. basicaly the way it worked was, the band is taped to the bag,m when you pull the band back, you pull back the bag also, which pucks in air into the hole in the bottom of the bin,but at this time the hole is actually the top of the cannon, as thats where the air enters and comes out.

now when the air is being sucked into the bin, our teacher also had a hose from a fog machine attached to it, which made the bin suck up air, now when he let the band go when the bin was full of air, a ball of air shot out, and the fog remained inside that air ball so we could see where the ball went, which was around 20 meters, anyway, the fog ball could nock over polystyrene cups from 20 meters.

i want to know exactly how to build one of these as i cant really remember how they look like as i have forgotton, i was reminded of these once when i saw one being used on rollercaoster, in the minishow, elliot and the surfing scientist.

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Kiteman7 years ago
Look for a vortex cannon.

Cut a hole in the bottom of the bin, about the size of a tea plate.

Cut the garbage bag into a large sheet, cover the open end of the bin with in, and hold in place with tape.

Tape the band to the middle of the bag as a handle.

Pull the bag out, fill with fog, and then gently-but-quickly push the bag into the bin.
Kiteman Kiteman7 years ago
Check out this YouTube video (which won't embed):
Kiteman Kiteman7 years ago
I can't find a reference right now, but I heard that the chap that invented these didn't use smoke.

He filled his cannon with smelly stuff, then sat at his town-house window and shot invisible vortices at passers-by, who would suddenly find themselves surrounded by an inexplicable stench.

oldmanbeefjerky (author)  Kiteman7 years ago
wow thanks, thats what ive been looking for, but in that first answer you posted, you said push the bag in, when i know for a fact that the ruber band, or bunji cord is whats supposed to push the bagin, was that a mistake, or did you actually mean that you supposed to push the bag in your self, becaus when i last used one, it had the rubber band do all the work
It depends.

The toy ones use a rubber band to pull the bag inwards sharply ("Airzooka", and the cannon in the video).

You have more control over the vortex if you push the bag in by hand, plus it is easier to build.