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View Full Version : Why does lighting a match eliminate "certain" odors?


WildCat
21st August 2003, 06:36 AM
You know the odor I'm talking about, most of us probably keep a book of matches in the bathroom for this purpose. But why does it work? Does the burning match and sulphur smell merely cover up the offending odor, or is something else at play? Enquiring minds need to know!

Sundog
21st August 2003, 07:37 AM
Originally posted by WildCat
You know the odor I'm talking about, most of us probably keep a book of matches in the bathroom for this purpose. But why does it work? Does the burning match and sulphur smell merely cover up the offending odor, or is something else at play? Enquiring minds need to know!

I've always thought this was an urban legend. Any effect would have to be from the sulfur dioxide combining with certain "other" molecules in the air, and that seems unlikely. The match itself can have no effect, as combustion only takes place right where the fire is - one thing that definitely ISN'T happening is that you are "burning up" the offending odor. I think it's just a case of the sulfur dioxide, being a more pungent odor, drowning out the other odors.

Ziggurat
21st August 2003, 08:38 AM
My impression has always been that it's the carbon in the smoke that absorbs the offending odor. Charcoal is used for filtering a lot of stuff from air and water, so this seems plausible to me. At any rate, I can testify that empirically it does work, whatever the details of the mechanism.

zakur
21st August 2003, 09:11 AM
It doesn't eliminate it, it just covers it up. The smell receptors in your nose are essentially overwhelmed by the sulfur in the match, which acts as "olfactory camouflage" until the flatus dissipates.

Sundog
21st August 2003, 09:28 AM
Originally posted by Ziggurat
My impression has always been that it's the carbon in the smoke that absorbs the offending odor. Charcoal is used for filtering a lot of stuff from air and water, so this seems plausible to me.

I doubt it very much. It would be carbon dioxide, not free carbon, and in that case I would expect opening a can of soda to work equally well. Carbon dioxide is quite stable and isn't likely to mix with anything else in the air.

hgc
21st August 2003, 09:54 AM
My experience is that it's the smoke from putting out the match, more than the striking of the match (source of sulfur smell), that works the magic.

American
21st August 2003, 10:10 AM
It almost certainly eliminates the odor (not just cover it up), turning most of it into carbon dioxide and water, NO, NO2, SO2 and other small inorganics.

I think the key it to move that flame around so it contacts most of the smell, and a lighter works as good as a match.

Soapy Sam
21st August 2003, 03:26 PM
Never heard of this before...what's the explosion risk?

WildCat
21st August 2003, 03:43 PM
Originally posted by Soapy Sam
Never heard of this before...what's the explosion risk?
How much haggis did you eat?

arcticpenguin
21st August 2003, 03:44 PM
Originally posted by Soapy Sam
Never heard of this before...what's the explosion risk?
Wikipedia (http://www.wikipedia.org/wiki/Lighting_farts) says:

At least one patient is known to have exploded while undergoing cauterization of a rectal polyp. An electric spark ignited the patient's intestinal gases, resulting in a six-inch (15-cm) hole in their large intestine. However, this was sewn up, and the patient recovered [1].
Note: They give references, but I didn't check them myself.

Chupacabras
21st August 2003, 04:31 PM
Originally posted by Soapy Sam
Never heard of this before...what's the explosion risk?

Look for Iconoclast's avatar to find an answer.

I have seen students burn their gas, live. OTOH, "if it is necessary", I light a wax candle and leave it in the bathroom. After a few minutes you can go in safely - no sulphur, no carbon, no nothing. My guess is that the pheromones oxidate with the heath... That, or the saints feel sympathetic with me! :)

BTox
21st August 2003, 08:17 PM
Originally posted by American
It almost certainly eliminates the odor (not just cover it up), turning most of it into carbon dioxide and water, NO, NO2, SO2 and other small inorganics.

I think the key it to move that flame around so it contacts most of the smell, and a lighter works as good as a match.

I vote for the cover-up theory. Or perhaps better dispersion and dilution. Sounds very implausible to me that waving a match for a few seconds would signficantly combust a very large and diffuse cloud of VSCs.

American
21st August 2003, 08:42 PM
Originally posted by BTox
Sounds very implausible to me that waving a match for a few seconds would signficantly combust a very large and diffuse cloud of VSCs.

Key word "diffuse".... I don't know- what's the flashpoint of rotten coffee grounds?!



Natural gas exsplosion, house fully involved
http://www.highridgefire.com/fire102799.jpg

UnrepentantSinner
21st August 2003, 08:56 PM
Originally posted by zakur
It doesn't eliminate it, it just covers it up. The smell receptors in your nose are essentially overwhelmed by the sulfur in the match, which acts as "olfactory camouflage" until the flatus dissipates.

That was my impression as well. It's the same as putting cologne on when you've got B.O. You'll still stink, but the plesent odor of the cologne will overpower the rank stank.

RSLancastr
21st August 2003, 09:27 PM
I've always assumed the flame from the match or candle burned the offending gasses somehow.

Of course, being anosmic, I don't even have impirical evidence to go on... :(

The Central Scrutinizer
21st August 2003, 10:10 PM
Mine doesn't stink, so it's a moot point.

EdipisReks
22nd August 2003, 12:15 AM
mine smells like roses.

hgc
22nd August 2003, 06:18 AM
Originally posted by EdipisReks
mine smells like roses. Does not a brown clowd by any other name smell just as foul?

Keneke
22nd August 2003, 12:51 PM
Smells are, essentially, particles of the smelly substance in the air, going in your nose, and your nose sensing it. (That knowledge alone makes me want to not smell farts! Yuck!) So, lighting a match and waving it around could conceivably interact with smelly things in the air, but I'd wonder if the flow of air in the combustion (cool air being drawn in from below because of the hot air rising out of the top of the flame) would be as conducive to capturing smelly particles as it seems. Perhaps.

I'd think it would be a mixture of all three causes - overpowering sulfur, burning smelly particles, and carbon soaking up smells - that would do it. I can't even guess what would be the most efficient, though.

Sundog
22nd August 2003, 12:54 PM
Originally posted by Keneke
Smells are, essentially, particles of the smelly substance in the air, going in your nose, and your nose sensing it. (That knowledge alone makes me want to not smell farts! Yuck!) So, lighting a match and waving it around could conceivably interact with smelly things in the air, but I'd wonder if the flow of air in the combustion (cool air being drawn in from below because of the hot air rising out of the top of the flame) would be as conducive to capturing smelly particles as it seems. Perhaps.


No way is it combustion. Imagine the small snake-shaped path described by the waving match. ONLY the material in the immediate area of the match will be oxidized. We should be very glad this is so, or there would be a big WHOOF sound and your eyebrows would be burned.

jayrev
22nd August 2003, 01:01 PM
Originally posted by Sundog

We should be very glad this is so, or there would be a big WHOOF sound and your eyebrows would be burned.

That happens to me even before I light the match. Maybe I should reduce my dairy intake.

odorousrex
22nd August 2003, 01:26 PM
I was guestimate a combination.
The flame consumes any remaining methane. The charcol absorbs and lingering odor, and the sulfur dioxide released overwhelms what's left.

Sundog
22nd August 2003, 01:29 PM
Originally posted by odorousrex
I was guestimate a combination.
The flame consumes any remaining methane.

Nope. Try this with any other petroleum gas. WHOOF.

We can see combustion. Oxidation is taking place exactly where that fire is - nowhere else. No way is the flame from that match touching even a small fraction of the methane molecules.

Tez
24th August 2003, 04:00 PM
Originally posted by Keneke
Smells are, essentially, particles of the smelly substance in the air, going in your nose, and your nose sensing it. (That knowledge alone makes me want to not smell farts! Yuck!) So, lighting a match and waving it around could conceivably interact with smelly things in the air, but I'd wonder if the flow of air in the combustion (cool air being drawn in from below because of the hot air rising out of the top of the flame) would be as conducive to capturing smelly particles as it seems. Perhaps.

I'd think it would be a mixture of all three causes - overpowering sulfur, burning smelly particles, and carbon soaking up smells - that would do it. I can't even guess what would be the most efficient, though.

If by the "smelly things" you mean particles of fecal matter, then youre simply wrong - which will probably come as a relief!

The smelly stuff in a fart is primarily hydrogen sulphide, and perhaps small amounts of mercaptans (the chemicals that make paper mills smell). Other constituents are methane (though some folks emit methane, others dont), nitrogen, oxygen etc. None of these are pathenogenic - so your revulsion is ultimately misplaced....

Incidentally, vegetarians are fond of making the argument that your body "really" evolved to eat veggies, and that it cant "really" deal with meat (the supposed proof being thats why we have to cook it). I simply point out that on a pure meat diet you essentially do not fart - your body has the enzymatic ability to digest meat without bacterial assistance (unlike carbohydrates)...

As to the match thing - I've never tried it. My guess is that its simply a coverup effect as others have mentioned - although if a cigarette lighter really does work just as well then it must be something more complicated...

MathewOrman
24th August 2003, 04:34 PM
Originally posted by WildCat
You know the odor I'm talking about, most of us probably keep a book of matches in the bathroom for this purpose. But why does it work? Does the burning match and sulphur smell merely cover up the offending odor, or is something else at play? Enquiring minds need to know!




Simple!
The flame temperature breaks up the molecules.
Flame is often used in sterilizing.


Sincerley,

Mathew Orman
www.ultra-faster-than-light.com
www.radio-faster-than-light.com

Tez
24th August 2003, 05:00 PM
Originally posted by MathewOrman





Simple!
The flame temperature breaks up the molecules.
Flame is often used in sterilizing.


Sincerley,

Mathew Orman
www.ultra-faster-than-light.com
www.radio-faster-than-light.com

Stupidity incarnate.

No pathenogens.

Not enough heat to sterilize a room anyway.

Why do I reply to morons? Someone help me...

Keneke
27th August 2003, 09:13 AM
Originally posted by Tez

The smelly stuff in a fart is primarily hydrogen sulphide, and perhaps small amounts of mercaptans (the chemicals that make paper mills smell). Other constituents are methane (though some folks emit methane, others dont), nitrogen, oxygen etc. None of these are pathenogenic - so your revulsion is ultimately misplaced....

Ah yes, I forget the fact that sh*t is a heterogeneous substance.