This fire bottle is a quick and easy alternative to the Barking Dog chemistry demonstration. The bottle displays a bright blue (or other color) light, plus it emits a woof or bark. Several websites call this project a "bottle fire vortex" or "bottle fire tornado", but the flame propagates as a wave down the bottle, without spinning. Of course, you could spin the bottle on a carousel or turntable.
- glass bottle
- alcohol, at least 70%
- long-handled lighter
- Pour a small amount of fuel into the bottle. You want 1/2 cm to 1 cm of liquid in the bottom of the bottle.
- Cap the bottle or cover the top with your hand, whichever works.
- Shake the bottle.
- If you have fuel on the lip of the bottle, wipe it off or blow on the bottle to evaporate the fuel. Otherwise there is a good chance the flame will be restricted to this small area of the bottle. It is not a concern; just reduces the quality of the display.
- Carefully light the vapor just inside the mouth of the bottle.
- The flame should go out on its own, but if it does not, simply cover the mouth of the bottle and suffocate the flame.
- Each "run" uses up the oxygen in the bottle, which the fire needs in order to burn. You will need to blow fresh air into the bottle. You can blow into the bottle or else use a straw or tube. You probably will not need to add more fuel. Just add air, cover and shake the bottle, uncap it, and ignite the vapor.
- If you like, add a flame colorant to the fuel (e.g., boric acid for a green flame). Simply sprinkle some of the colorant into the bottle. Most colorants are not consumed by the flame, so even if you get to a point where you wish to add more fuel, you will not need to add more colorant chemical.
Notes on Materials
You can use just about any bottle you want, but do be sure it is glass! Plastic will melt. Also, the shape of the bottle, especially its neck, affects the sound that will be produced. You may wish to experiment with different types of bottles. I have had good success with a glass cola bottle and a large cylindrical glass water bottle. If by some miracle you have a giant graduated cylinder, go for it!
You can use other liquid fuels, too. You want some water in the fuel so that it will stick to the sides of the glass. You can add chemicals to color the flame, too. Some of these will dissolve better in pure alcohol, which you can dilute with water or mix with rubbing alcohol.
Long Handled Lighter
You could drop a match in the bottle, but then you will need to fish it out to repeat the project. Flame will shoot out the top of the bottle, so don't use a short lighter. A candle is another good option.
Safety InfoYou know the drill. This is fire. It can burn you! Perform this project under competent adult supervision. Do not set the fuel next to your glass container. Do not perform this project on a flammable surface or near flammable objects (e.g., do not lean into the bottle with long hair, do not light the bottle next to drapes, etc.). Do be prepared to put the fire out in case of an accident. Having said all that, this project works well indoors. Actually, I recommend you try it indoors because you will get the best effect in still air, with no wind.
Watch a video of this project.