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Spontaneously-Combustible Flour? Answered

Well, I know that if you put finely powdered stuff, like flour or sawdust, it has a chance that a spark will form and create a huge (and I am talking HUGE) fireball. Watch this video (those stupid kids):



The above video amuses me: They state do not try this at home, but they apparently did. They obviously didn't know what they were doing, because if they had, they wouldn't have risked their friend (or at least severely burning him).

Does anyone know the percentage chance that this will happen if, say, I took a cup of flour and use a shaker (or just a shaking motion) to spread it out into the air? If I wanted some flour to combust, would I be better off (not in health, in entertainment) to just use a match?

Oh, and yeah, I am 13, but I am a bit more mature than other people I know that are my age. I'm glad they don't know about this site, because if they did, they would already be . (Seriously.)

Thanks in advance!

22 Replies

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mudrunner111 (author)2007-07-30

Depending on weather conditions and grounding involved static electric charges can be enough of a spark to ignite the air fuel mixture. Earler John had responded with a consideration about how water does not burn. I agree that it in and of itself in the H2O state it does not burn, but when it is seperated into it's original components of hydrogen (which Burns) and oxygen (which Supports combustion) you can and will have a very interesting (and DANGEROUS) fire! This change can be caused by a super heated fire that in a moment changes water into two seperate elements and bang! People have had fun but others have received serious pain and life long injuries or death. Please be safe and if you do not know what you are doing leave it alone.

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nonickname (author)mudrunner1112009-05-18

Water isn't flammable- in the sense you mean. As it is a combustion byproduct energy would have to be used to sever the hydrogen bonds- more energy than would be obtained by combusting the byproducts. Think of this. If you electrolyze water to obtain 2H2 and O2 then burn them, it takes more energy to split the bonds than energy that is gained by oxidizing hydrogen. It's a basic law of science. So basically, the so called "superheated fire" you speak of does not gain energy, as it loses it through heating and severing bonds. If that were even to work. Magnesium and certain other materials can sever hydrogen bonds of water to use an oxygen atom for combustion and leaving a hydroxide ion. It still takes energy to sever the bonds, so it doesn't count. And before somebody mentions throwing water on an oil or grease fire- it does not combust. The water simply affects the surface area of the substance but unless the fire is being starved of oxygen energy will be lost through heating the water to vapor. So you're kind of correct.. but you're not. (don't take it hard, eh?)

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nonickname (author)nonickname2009-05-18

Oh btw, you can do this with most finely powdered things. I load the barrel of my air cannon with sulfur and fire it over a fire. The stench is..bad.

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KentsOkay (author)2007-07-02

I did something similar. Take a 4" pipe, that is 4ft long and hang in a vertical position over a large candle, so that the candle flame burns inside the pipe but still has oxygen flow. Wearing gloves and glasses, use a sifter to lighlty sift the flour down the tube, with the candle lit and keeping your face away. If dne just right, the flour will ignite and produce a saticfactory bang and flame. I have only been able to do it once out of numerous attempts. I'm only bothering telling yu this because you are definetly mature for your age. If you ever make any Instructables on the subject of bangs and flames, add them to my group, the Intergallactic Brotherhood of Bomb and Weapon Masters. Good Luck

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CameronSS (author)KentsOkay2007-07-19

Here's a slightly safer version--if you take "safer" to mean "standing farther away".

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John Smith (author)CameronSS2007-07-24

Mr. Wizard (search Google) did that with a paint can!

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CameronSS (author)John Smith2007-07-29

I know who Mr. Wizard is...I have one of his books!

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Bran (author)KentsOkay2007-07-02

That sounds interesting. And on the "you are definitely mature for your age" part, well, my sister is a nurse in the burn unit at the local hospital so I here of so many injuries all the time. She just recently received a 7 year old boy from some other county who has locked himself in his bedroom and was playing with matches. His mom heard him screaming, but by the time she got his locked door open, he was already engulfed in flames. He almost died yesterday, but he could still die. So, I know of the dangers. Same with people driving fast/drunk/stupidly. My aunt died in a car crash. The list goes on....

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NachoMahma (author)KentsOkay2007-07-02

. A half-a-cup of flour, fine sawdust, etc, flung over a camp fire, has an effect similar to the video, just a little more "intense." The stuff will flash back at you if you don't throw it hard enough, so be careful.

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user

In 8th grade, there was a movie we saw in science class. where an explosives expert demonstrated the same thing. I've tried it, with no success.

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mudrunner111 (author)2007-07-19

Many types of dust can be combustable and ignited by as little as a stray spark. Many grain elevators have blown up due to grain dust becoming a fine powdered mist at the proper air/fuel mixture of 16 to 1. Large concrete steel reinforced grain elevators have been blown up by this happening. Coal mines is another location for this type of explosion. Even aluminum fine powdered dust can be ignited (seen this one done at work) not to mention what can happen with magnesium if that find dust finds an ignition source. Also think on this. Water (H2O)is made up of what? Hydrogen and Oxyger. If you heat it up quickly enough water will seperate into the original components and instead of putting out a metal fire will support the combustion process and make the fire hotter. This is why on metal fires we use what is called Class D extinguishing material. Sand, dirt special other materials that will not change composition in a real hot metal fire. Stay safe and leave this one alone is just a suggention for survival.

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John Smith (author)mudrunner1112007-07-24

I found this, on the topic of burning water.

An excerpt:
Water doesn't burn because it's already an ash. You are correct that water
is made of oxygen and hydrogen, and you are also correct that hydrogen is
flammable. However, oxygen is not flammable. Oxygen is an oxidizer, that
is, it supports combustion. A jet of oxygen will NOT burn in air! When
oxygen and hydrogen are mixed, they can chemically combine, generating lots
of heat energy. When this reaction is complete, the product is water. So,
water is what is created when hydrogen burns.

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acer73 (author)2007-07-19

I would do this last year. But on a much smaller scale. I'd spill rubbing alchol on the drive way, light it and then throw a handful of flour above it. It worked 100% of the time

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alex26i (author)2007-07-02

Custard powder, or powdered milk works better. There is also Dragon's breath, which is lycopodium spores, burns much cleaner. My guess is, the gun had a spark inside when it launched. All these powders can only ignite in a mist like form, you can't light FLOUR up if it is in a pile. The biggest danger for this guy was inhaling the dust. That was my guess why he was on the ground for so long.

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Lextone (author)alex26i2007-07-19

Powdered coffee creamer works great too. These are nothing more than fat in a powder form. Take a hand full and throw it at a camp fire....whoomp!

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Kiteman (author)2007-07-02

Many slow-burning solids will explode if suspended as a fine powder. Flour, coal-dust, even sugar have all exploded catastrophically.

It is a "standard" demonstration to punch a hole in the side of a large tin, feed through a length of rubber tube, lay flour around inside the tin, stand a lit candle in the tin, push on the lid and then blow down the tube.

The puff of air lifts the flour into the air, it is lit by the candle, the combustion is restrained for a moment by the tin, and BANG, off comes the lid.

Generally fond as I am of things that go bang, the flour bomb makes me nervous to do - I have my mouth around a tube that feeds directly into an explosion.

http://en.wikipedia.org/wiki/Flour_bomb

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Weissensteinburg (author)2007-07-02

I know that flour is extremely flammable, but I don't think it spontaneously com busts..im betting that there was some kind of small flame..im not an expert on spud guns, but I know some people use hair spray and a bbq ignitor to shoot their spuds..so if they did have an explosion to launch the flour, then theres a good chance it will ignite.

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user

The flames caused by the igniter and hairspray would have caused the flour to burn.

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NachoMahma (author)2007-07-02

. Almost any fine organic dust will ignite/combust, though not necessarily spontaneously. Sawdust can be very hazardous.

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