5-Gallon "Whoosh Bottle"

This video is somewhat subpar compared to the others that we've done (and those that we're planning to do.) It is a pulsejet, or "whoosh bottle": a five-gallon water jug with around 15mL of methanol and a pinch of potassium nitrate (which oxidizes and adds color). The top of the bottle is then lit with a match on a stick, creating a pressure differential that sucks in the very flame it is producing. We then try the experiment again but with a PVC reducer to make the video original, and create a much narrower, vigorous flame. Expect new videos, including the "big one", ferrofluid synthesis, in the future.

Category:

Science & Technology

Tags:

• methanol
• whoosh
• bottle
• methyl
• flame
• tall
• alcohol
• jam
• jar
• pulse
• jet
• pressure
• differential
• match
• on
• stick
• ethanol
• the

[loltehinternet]

Is pyroscillation a word?

[dbc616]

I doubt it

[mrericsully]

Good video.

The first test had a very slow moving flame, did you do that with just methanol and potassium nitrate or was the methanol dilute with water?

I do my whoosh bottles with ethanol and then for a slow burning one I use a 50-50 water-ethanol mix.

I would say that the slow burn is more like a regular engine [although they do pulse at the end and the fast burns are more like the pulse jets.

[dbc616]

We did it with just methanol and potassium nitrate nothing else, we were actually surprised at how slow it burned.

[mrericsully]

OK follow up question- had you recently used the bottle for a whoosh bottle or recently washed it out? The first choice could mean that there was still quite a bit of CO2 in there an so less oxygen would be available for burning which could cause a slow burn. The second choice could put a significant amount of water vapor in the jug maybe taking the place of the water diluting the alcohol.

Another possibility I guess would be how well the methanol was shook up inside the bottle.

[dbc616]

We had done one around 2 hours before in the daylight, and we could hardly see it, so we waited until nighttime. We just left it on its side so the CO2 could come out. We usually use an air compressor to get rid of the by-products, but we didn't have one handy at the time.

[antiswattt2]

whisteling AND vibrating.. rofl not my fault your words could be misunderstood xP i have done this alot with soda cans.. just be careful not to get burnt.. its a really hot flame q: haha.. just fill it with lighter gas, and put a flame to the hole.. you reminded me of that gasoline and acetone makes gasses.. so i could just put in some gasoline to constantly make gases.. :D

[WooshMan07]

I like it, i dot these about 1 a week, there just fun to do. i like isopropyl alcohol my self, cheap, and i say keep the methanol for drinking...LOL JK... i know its denatured. i would have to say its the CO2 and some H2O left in the bottle from the last combustion. so times if i do to many burns in a row I actually dilute the Iso. to much with all the H2O left in the bottom. I also use an air compressor to blow my bottles out. I planning on doing a super bottle soon.

[mrericsully]

I've found that the CO2 comes out better if it is set neck down so that it drains out. I like the air compressor idea though.

My guess is that maybe there was some CO2 still left in resulting in your slow burn. I'll have to try to recreate it myself soon.

[nshoebox]

This was one of my favorite demos in chemistry.