How would one find the speed of a smell (speed from emitter body to recievers in the nose)? Let's assume STP, Earth's atmosphere, and the smell is sulfur.
2006-08-10 11:34:41 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
Smells are just chemicals. The speed that chemicals diffuse in the air is predicted by Graham's Law when you compare two gases.
Use oxygen as your standard gas.
The ratio of the speed of diffusion on the smell compared to oxygen is equal to the square root of the inverse of the mass of the oxygen molecule divided by the mass of the molecule of the smell.
The molecule of sulfur has 8 atoms of sulfur in each molecule, oxygen has two atoms per molecule. The mass of sulfur is 32 and oxygen is 16. The mass of their respective molecules are 8x32 and 2x16 or 256 and 32. Take the ratio of the two, oxygen over sulfur is 32/ 256 or 2^5/2^8 or 1/8. Take the square root of 1/8 is 0.354.
So the speed of the smell is about 1/3rd of the average speed of the molecules of oxygen in the air.
2006-08-10 11:41:45 · answer #1 · answered by Alan Turing 5 · 5⤊ 2⤋
ahahhaha that's a great question... so what you are REALLY asking is what is the speed of a fart!!!
I think it depends on if there are any air currents in the room... but certainly a smell will diffuse over time even in calm air of uniform temperature (convectionless).
I know that farts can be hot so they rise... assuming you let out a colder fart though, the average speed of a gas molecule is VERY fast but it interacts with lots of other fart molecules and air molecules. So it would depend on the mean free path of said fart molecule, which is pressure-related.
I'd say about a minute to travel a meter. Then get the gas mask.
2006-08-10 11:39:31 · answer #2 · answered by figaro1912 3 · 2⤊ 0⤋
The rate of diffusion (which is what we're dealing with here) depends on the mass of the object diffusing, and in this case, which type of sulphur molecule you're referring to.
But I've linked a general equation for it that has been simplified:
http://www.chem.umn.edu/services/lecturedemo/info/Diffusion_Rates.html
2006-08-10 11:39:46 · answer #3 · answered by ymingy@sbcglobal.net 4 · 0⤊ 0⤋
it would depend on windspeed as smell is particulate based. it would also depend on wind direction and air density and pressure.
2006-08-10 11:40:18 · answer #4 · answered by rosends 7 · 0⤊ 0⤋
180 mph
2006-08-10 11:39:40 · answer #5 · answered by The Guy 3 · 2⤊ 1⤋
Go here and find out...
http://en.wikipedia.org/wiki/Diffusion
2006-08-10 11:40:32 · answer #6 · answered by Anonymous · 0⤊ 1⤋