Take the Screen, roll it into a cylinder that will stand upright on the lazy susan, making a cage. Staples work just fine to make the cylinder.
Fill the bottom of a bowl with some lighter fluid. Drop a lit match into the bottom, and it will catch on fire. It's a good idea to use a little fluid at first, then work your way up to get the right sized tornado.
Put the bowl in the center of the lazy susan, place the screen cylinder around the bowl (you might have to fasten it to the turntable with a couple of pieces of tape.
SPIN the lazy susan slowly, and watch a pillar of flame rise up inside the screen!!!
This creates a flame tornado that extends to the top of the screening!
Convection and combustion are the two basic principles taught here. By spinning the tube, you increase the rate of evaporation of the lighter fluid, and improve the air:fuel mix, which burns hotter and higher than with just the bowl alone.
I did this demo with a group of 5th graders at our local elementary school, and they loved it. Definitely add a disclaimer to this one... don't want the kids burning down the house. And keep a fire extinguisher handy just to be extra safe.
If you really want to go over the top, use an old record player instead of the lazy susan, and gradually step up the speed... cool effect.
Slashdot Mirror
This is a great demonstration that really gets some oohs and aahs, and is very easy and relatively safe.
Equipment:
1. Lazy Susan Turntable (about 12" diameter)
2. Cereal Bowl
3. Ordinary Barbeque Lighter Fluid
4. Window Screen Netting
5. Match
Take the Screen, roll it into a cylinder that will stand upright on the lazy susan, making a cage. Staples work just fine to make the cylinder.
Fill the bottom of a bowl with some lighter fluid. Drop a lit match into the bottom, and it will catch on fire. It's a good idea to use a little fluid at first, then work your way up to get the right sized tornado.
Put the bowl in the center of the lazy susan, place the screen cylinder around the bowl (you might have to fasten it to the turntable with a couple of pieces of tape.
SPIN the lazy susan slowly, and watch a pillar of flame rise up inside the screen!!!
This creates a flame tornado that extends to the top of the screening!
Convection and combustion are the two basic principles taught here. By spinning the tube, you increase the rate of evaporation of the lighter fluid, and improve the air:fuel mix, which burns hotter and higher than with just the bowl alone.
I did this demo with a group of 5th graders at our local elementary school, and they loved it. Definitely add a disclaimer to this one... don't want the kids burning down the house. And keep a fire extinguisher handy just to be extra safe.
If you really want to go over the top, use an old record player instead of the lazy susan, and gradually step up the speed... cool effect.