how is smell measured?how does it travel?
817312
Smell is not measured.  The chemicals (molecules) that are detected can be measured and identified using instruments like gas chromatographs.\n\nFlowers and many natural smells are composed of large complex molecules which do not travel very far in the air.  Most artificial smells are made from small simple molecules which have a high vapor pressure and travels great distances.\n\nCheck out the references below:
401998
You can use a spirometer to do it. Please check out this link I am giving you, it will solve your problem. They have really done it well\nhttp://intranet1.sutcol.ac.uk:888/NEC/MATERIAL/PDFS/HUM_BIO/AS_HUMAN/23U2_T2.PDF\n(We can measure the volume of air moved by the lungs using a. spirometer . The ... air min. −1. with a breathing. rate of 18 breaths min ...)- excerpt from the site.
846092
If you mean the biology term "active transport" I can answer...\n\nCell fluids have stuff dissolved in them like oxygen, nutrients, salt and different ions, etc... The concentration of this stuff inside the cell usually must be equal to the concentration of the stuff in the fluids outside the cells. "Dissolved Stuff" usually moves from areas of high concentration to areas of low concentration to balance out the amounts in both areas. \n\nThink of opening a bottle of perfume in a room. Gradually the scented molecules of perfume make their way around the room and, if given a long enough time, fill the room to an equal concentration. You could tell by observing that the smell of the perfume would be more or less the same strength everywhere in the room.\n\nWell, this process is diffusion- movement of fluid (in this case, perfume and air molecules) from high concentration ( the bottle) to low concentration (the room).\n\nActive transport is the opposite in many ways- it is the movement of fluid from low to high concentration. Sort of like putting the perfume smell back in the bottle. You might realize that this is not the natural tendency for things and you'd be right. Acitive transport is "active", requiring energy and or specialized cell structures to happen. \n\nDiffusion and active transport take place through semi-permeable membranes in plant and animal cell structures- sort of like a layer of plastic with very very very tiny holes poked in it that allow only certain sized molecules to get through.\n\nHope this helps!
746094
Certain things give off a different smell when heated but mostly I don't think you can differentiate. The sensation of smell is caused by particles of the thing in question not by chemicals released.
906038
(m)\n\nSeventy to seventy-five percent of what we perceive as taste actually comes from our sense of smell. Taste buds allow us to perceive only bitter, salty, sweet, and sour flavors. It's the odor molecules from food that give us most of our taste sensation. \n\nWhen you put food in your mouth, odor molecules from that food travel through the passage between your nose and mouth to olfactory receptor cells at the top of your nasal cavity, just beneath the brain and behind the bridge of the nose. If mucus in your nasal passages becomes too thick, air and odor molecules can't reach your olfactory receptor cells. Thus, your brain receives no signal identifying the odor, and everything you eat tastes much the same. You can feel the texture and temperature of the food, but no messengers can tell your brain, "This cool, milky substance is chocolate ice cream." The odor molecules remain trapped in your mouth. The pathway has been blocked off to those powerful perceivers of smell--the olfactory bulbs. \n\nOf all our senses, smell is our most primal. Animals need the sense of smell to survive. Although a blind rat might survive, a rat without its sense of smell can't mate or find food. For humans, the sense of smell communicates many of the pleasures in life--the aroma of a pot roast in the oven, fresh-cut hay, a rose garden. Smells can also signal danger, fear, or dread. \n\nAlthough our sense of smell is our most primal, it is also very complex. To identify the smell of a rose, the brain analyzes over 300 odor molecules. The average person can discriminate between 4,000 to 10,000 different odor molecules. Much is unknown about exactly how we detect and discriminate between various odors. But researchers have discovered that an odor can only be detected in liquid form. We breathe in airborne molecules that travel to and combine with receptors in nasal cells. The cilia, hairlike receptors that extend from cells inside the nose, are covered with a thin, clear mucus that dissolves odor molecules not already in vapor form. When the mucus becomes too thick, it can no longer dissolve the molecules. \n\nAnimals depend on odors secreted from their bodies to communicate. For humans, odors communicate a variety of messages, depending on the odor and the person receiving it. The aroma of a baking apple pie sends one message when someone is hungry and quite another when that person has just finished a six-course meal!
95159
The olfactory bulb is the sense of smell. It is an accessory nerve sense. It adapts quite readily. That is why we get used to a smell and we can not smell it anymore. For instance, if you spray perfume on, you can only smell it for a short while. These sensory bulbs adapt and you can no longer notice it, another person walks up and notices quite readily.
273925
The simplest way is spectography. if you are speaking of a breathalizer test it is via conductivity.
207024
It depends on the permeation time of the smell (ie. dense gases spread faster in a closed environment than less condesed ones.)  Wind helps as well if it is an open environment.\n\nTo put it simply smell has too many variables to create a unified theory of odor permeation.\n\nBut I do know my farts seems to move fasters than other odors.
576006
50 times the speed of smell
906945
Smell. The rest I would not like to lose.
69568
None, unless you pour something into it, then it is a measure of 1.5 oz. \n\nHope it is something yummy.
73233
It smells sort of like a skunk. Its a unique smell but skunk odor is probably the closest.
1072569
does masturbation have a smell.
367999
It weighs the amount that the air inside it weighs.
341106
it's called the process of diffusion. as a smell spreads out its molecules use the air molecules to move away as gas molecules are so free. soon there is very little atoms of the fart smell left that it is unsmellable to the human nose although it's never truly gone!
12571
there are lots of devices that "smell," like the ones we use for natural gas, CO, nitrogen sulfide, etc.. i guess it depends on what you are trying to smell..
744274
sense of smell loss is refered to as - anosemia\nnot sure of the others