A science question...?

Question

In physical terms, what exactly IS a smell or odor? OK, if it's a fart, I know that you're smelling gases such as methane and sulfur dioxide. But what about wet leaves or fried chicken or cookies baking? When you catch the smell of it, what exactly is being sensed by your olfactory nerve and taste buds? Is an odor composed of invisible particles of the substance or something like that?

Answer 1

The sense of smell is one of the most fascinating of all of our sensual receptors. It is also one of the most critical for all animal species. As humans, we can detect and distinguish more than nine thousand odors. We use our sense of smell for any number of different things, including enjoying the aromas of our favorite foods and beverages as well as deciding whom we want to associate with based on smell. We can use it to detect danger as in a fire or a gas leak, and we can use it for fun like in reading scratch and sniff books to our children. Over the course of the past twenty years, science has made extensive study of the human sense of smell. The science community can now tell us both how our nose detects odor molecules and how the brain is able to deal with that information once it is detected.

Every odor
your nose detects comes from molecules, tiny particles emitted from the object. Almost everything emits a smell, but some of them dont reach as far as others. For example, bread, onions, perfume, fruit, and similar things give off many light, volatile molecules that are long range. They float through the space around the object and eventually end up in your nose. Other objects, like steel for instance, gives off molecules, but they are not long range and do not float as easily. As a result, we might say it has no smell.

Your sense of smell kicks in when the molecules enter your nose. At the very top of the nasal passage, there is an area, around the size of a postage stamp, which contains a large patch of neurons. Actually, it contains millions of neurons, called olfactory receptor neurons. The area is called the olfactory epithelium. The interesting, and unique, thing about these olfactory receptor neurons is that they are unprotected. This means they can come into direct contact with the air you breathe in. Their projects, a bit like hair, increase the surface area they can reach. The projections are called cilia. As an odor molecule comes up the nasal passage. The cilia will trap it. This forces the olfactory receptor neuron that the cilia are attached to, to send a message to your brain and cause you to perceive a smell.

Not everyone perceives the same smells, though. Recently, scientists discovered that the ability to smell certain odor molecules is genetic. Your individual genome encodes your olfactory receptor neurons. Each of the receptors has a place where an odor molecule can form a bond with it so your brain can perceive the smell correctly. If the right molecule falls into the right place, you get the smell. If, however, you are missing a genetic sequence, or the correct genetic sequence has been damaged in that area, your olfactory receptors are unable to accept the molecule. As a result, your brain is unable to receive the electrical impulse, and you never get the smell. It is possible to regrow these olfactory neurons if they are damaged.

There are four zones of olfactory receptor neurons within your brain. These four zones can help to distinguish the quality of the odor, the intensity of the odor, and the type of odor you are detecting. Even babies in the womb have a sense of smell. By nine weeks into gestation, the nasal cavity has separated from the mouth. It is at this point that the olfactory receptor neurons are formed. By the thirteenth week of gestation, the connections between the babys brain and the olfactory receptor neurons are formed. From that point onward, the baby can smell throughout the gestation. Smelling does not require air; it simply requires the odor molecules, which can be transmitted through the amniotic fluid. In some scientific studies, a baby can recognize its mothers scent immediately after birth.

The sense of smell is often termed one of our chemical senses because it requires that we process the chemicals around us for use. Smell can alert us to danger, but it can also offer us a sense of recognition. Ever have someone wander by you wearing your mothers perfume? You probably immediately recognized it as such. The sense of smell, as complicated as it is, is one of our most powerful.

Answer 2

It is vapor. Any chemical substance vaporizes to some degrees at room temperature, which means some of its molecules break free from its surface and diffuse into the air. Some substances vaporize easier and than others: air fresheners, coffee, ...
Temperature has direct effect on the speed and the amount of vaporization for example a warm fried chicken has a stronger smell than when it is cold.
Plants and animals have special organs that produce special chemicals that cause their smell: the smell of the pines is because of the turpentine in their resin.

Answer 3

Yes, the sense of smell detects molecules of substances suspended in the air. If an object or substance is not releasing molecules into the air, you cannot smell that substance. Of course, some substances, like water, do release molecules into the air, but your olfactory detectors are not sensitive to those particular molecules.

Answer 4

I hope I don't gross you out. But the olfactory glands in your nose have receptors on them for molecules of whatever you are smelling. If you think sugar smells nice it's because your olfactory glands trigger releases of endorphins and dopamine when they pick up C6H12O6, and when you smell a fart.........sorry, that's what happens. Molecules of the thing you smell, is what is entering your nose. Makes farts all the more nasty.

Answer 5

i won't be able to give you a very scienctific answer, cause i haven't done this stuff in awhile, but basically the smell particles go up your nose, and every smell has a different shaped particle, that fits in a part of your brain/nose. So you smell when the particle fits in the part.

Answer 6

"Scientists" attack Christianity and "Christians" attack technology. How can technology be used to purpose non-repeatable phenomena. Did "guy" exist 7,000 years in the past? It relies upon on the way you define "guy." in case you define "guy" as somebody who can checklist historic previous, the respond could be "no." while i became attending college, many years in the past, C-14 courting became referred to as an "absolute" courting approach and constrained to 50,000 years in the past. Now it is seen a relative courting gadget. It has alway been seen as such by physicists and extends previous 60,000 years. C14 is created by bombarding the nitrogen loose on the suitable of the ambience with cosmic capability. If there is way less loose nitrogen, there is way less C14 created. much less C14 in an merchandise shows an older age. technology does no longer attack something. the 2d it does, it ceases to be technology. Scientists who take facets like that turns into monks of "technology" quite than observers of experiments and technology is all approximately repeatable technology. right here is the weak point of all courting structures. no person has ever examined them for 2 hundred,000 years... or perhaps 60,000 years. the perception that the forces that govern those structures are static is with out data. Even the assumption-approximately time has its limits. with out mass/gravity, time does no longer exist, in accordance ot Steven Hawkings. yet, then, the Biblical courting is likewise in keeping with assumptions by some nineteenth century bishop. How long is an afternoon if the earth does no longer rotate in terms of the sunlight... or if there isn't any sunlight. Then there is the project of randomness. If a pail of ice all of sudden began to boil, might or no longer it quite is a miracle or an twist of fate of threat? technology might say it became an twist of fate of threat in all risk basically to ensue as quickly as in 1000 billion trillion buckets of ice. in some unspecified time sooner or later, that that's threat and that that's supernatural attain a nexus.

Answer 7

d

Answer 8

I don't know.....good question though