Could something smell so much that it entirely disappears?
December 9, 2010 6:02 PM   Subscribe

Could something smell so much that it entirely disappears?

That is, could all of the particles that make it up completely expend themselves through the stinking process?
posted by goethean to Science & Nature (10 answers total) 7 users marked this as a favorite
Best answer: uh, moth balls?
posted by yeoz at 6:03 PM on December 9, 2010

Best answer: Do rubbing alcohol or nail polish remover count?
posted by parkerjackson at 6:06 PM on December 9, 2010

Best answer: Acetone. The term you are looking for is volatility.
posted by fatllama at 6:07 PM on December 9, 2010

Or sublimation.
posted by Sebmojo at 6:34 PM on December 9, 2010

Your question is unclear. Your olfactory senses fatigue easily. Presented with a new environment, the olfactory nerves can detect an odor, but then lose the ability to maintain the smell. Volatile substances such as turpentine will have a first impression odor that will no longer be noted after a few minutes.

As people age, the sense of smell becomes less acute.

Some volatile substances will outgas until they reach a state where the odor is no longer detectable.

So, three scenarios here. Most likely others I have missed.
posted by effluvia at 6:50 PM on December 9, 2010

When something gives off an odor, that means that our nose is detecting molecules that have emanated from the object. Some things, like pure alcohol, acetone, etc., can evaporate/sublimate completely. Water too, but water has no odor. Obviously, if something is going to disappear completely through this process, every part of it must be physically (chemically) able to do so.
posted by holterbarbour at 6:58 PM on December 9, 2010

It's not like smelling uses up molecules. You don't have enzymes to break down those molecules. They attach, cause the sensation, and break free from receptors. (Otherwise, you'd be using up your receptors as you smelled, and you'd become unable to detect a scent after exposure until you regrew new receptors.)

You become habituated to smells quickly. That means that a part of your brain interrupts the sensation before it reaches your consciousness. "Yeah, yeah, I already know it smells like car exhaust, enough already."

Some substances evaporate. Of course, that evaporation just makes it so that more molecules come into contact with your nose. If you sit in an airtight room with a pan of gasoline, and all of that gasoline evaporates, your nose will continue to be bombarded by gasoline smell. You'll become habituated to the smell and stop noticing it, but your nose is still catching molecules of gasoline.

But then, if somebody opens the door and a wind blows through the room, all of that evaporated gasoline will be blown away, and so in a sense, all of that gasoline will have been "used up" by evaporation.

Does that answer your question?
posted by nathan v at 7:43 PM on December 9, 2010

Best answer: It's not like smelling uses up molecules.

I think he means "smell so much" in the sense of "produce so much odor."

Sure, the phenomenon of odor does involve a loss of physical mass to the environment, although in the vast majority of cases it is only components of the objects mass. So fatllama and sebmojo have it right, an obect completely composed of something that is volatile (a liquid that readily evaporates) or which sublimates (a solid which transitions directly to the gaseous state without going through a liquid intermediate) could completely disappear into the air, and if its substance had a smell, it would have done so fully by the same process by which it produced odor. Your question is a little fuzzy because "smelling" is a fairly subjective state. A little zen in it: if it's molecules fill a room but no one ever goes in to smell it, has it been "smelling" in the sense you use the word in this question?

Anyway, yeoz's answer fits very well, a mass of pure naphthalene or para-dichlorobenzene could certainly sublimate entirely into the air and would produce, in an enclosed space, what could only be characterized as a powerful stench. I'd say the answer to your question is basically yes, as far as it goes.
posted by nanojath at 9:04 PM on December 9, 2010 [1 favorite]

Best answer: Isopropyl alcohol has a distinctive odor, and it evaporates completely at room temperature. Methanol likewise.
posted by Chocolate Pickle at 9:33 PM on December 9, 2010

Best answer: All condensed matter (solids and liquids) has a vapor pressure specific to that material. That means that these substances will continually sublimate or evaporate into the surrounding environment until the partial pressure matches the vapor pressure. If that point is never met (if the surrounding environment is well ventilated, say), then the substance will eventually vanish into the gas phase.

You can find the vapor pressure by looking at a phase diagram. At room temperature, for example, liquid water will evaporate until the partial pressure of water in the surrounding environment is about 3 kPa (3% of atmospheric pressure), then it will stop.
posted by Mapes at 5:39 AM on December 10, 2010

« Older Stern Re-Signs, I celebrate by car radio shopping....   |   Mefi-Wan Kenobi, you're my only hope Newer »
This thread is closed to new comments.