How does smell travel through water

Yet these smell maps are an overlooked part of everyday human existence, and this bias has bled into how scientists approach our senses. This utility expresses itself as behavior. Sweet smells draw bees to flowers, fueling pollination and the survival of crops. A wandering albatross can sniff a piece of floating carrion from three miles away , while sulfur compounds found in decaying animals were once added to mile gas lines, so turkey vultures and their giant beaks could be used to spot leaks.

Adult salmon cross hundred of miles using olfactory cues to find and spawn in their place of birth. The team is studying various animals to unpack these behaviors. Lucia Jacobs, an evolutionary ecologist at the University of California Berkeley, is examining rescue dogs to see how their skills stack against other super smellers, like hermit crabs and cockroaches.

Urban and Pitt mathematical neuroscientist Bard Ermentrout use infrared lights to track the whiskers of mice as the rodents follow odor trails. Ermentrout can then program those instincts into computerized mice. It was first published on June 9, Follow Nsikan Akpan on Twitter.

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See Subscription Options. Go Paperless with Digital. But step one in the road to building a smellbot is knowing what smells look like. Taffy odors Crimaldi, the COC project leader, studies the physics and architecture of scents. Virtual reality for smell These visual patterns create the basis for mathematical equations that calculate how odors move.

Bails on the Paris Climate Deal? Get smart. Sign up for our email newsletter. Sign Up. Support science journalism. Knowledge awaits. See Subscription Options Already a subscriber? It would seem strange that if you drop ink in water it takes ages to dissipate so how can the individual particles of a smell travel so far and apparently so fast? Vince is absolutely right in questioning the scenario in wildlife programmes where sharks apparently are attracted from a distance within a very short time after some smelly substance has been dumped in the ocean.

Water molecules in general are carried to the shark by water currents. If there are no water currents then it is molecular diffusion, the random movement of molecules that disperses the odour away from the source. Diffusion is an extremely slow process as Vince experienced in his ink experiment. In general the travel time of odour depends entirely on the local water velocity.

Near the water surface water velocities in the ocean can range between a few centimetres per second on a very calm day and several metres per second in a strong current. In summary, odour can theoretically be detected by a shark in several miles from the source and I would estimate that in the ocean this may take at least one minute to reach the shark at a distance of m. More likely it will need between ten and twenty minutes.

Finally the shark still needs to get to the source and that would take another seconds depending on the swim speed of the shark. If smelly things are dumped into the ocean don't expect a shark to be attracted from a distance in less than a few minutes. Short answer: Yeah! I was wondering this very thing lol. So it doesn't matter what way the water is flowing either?

Skip to main content. Earth Science. So, then, determining the speed of smell is a bit like figuring out how fast air travels It's not quite as impossible as that might sound, but tracking the progress of odorous compounds is definitely a lot trickier than following the movement of photons and sound waves.

Let's think for a moment about just where odors come from. Odors are the result of volatilized chemical compounds. In chemistry, volatility refers to the tendency of a substance to vaporize, or enter a gaseous state from its original liquid or solid form. Compounds are considered volatile when they have a low boiling point, which means large numbers of molecules can evaporate from the solid like a flower or the liquid like a glass of wine and enter the surrounding atmosphere.

Most odorous molecules are organic compounds, meaning they're carbon-based, although a few simple compounds like sulfur and ammonia also give off odors. This accords with our everyday experience - we know that plants and animals have odors, and by extension everything that that's made out of them, which can include everything from food and drink to wooden furniture to leather shoes.

And, just in case you're wondering, metal doesn't have a smell. If you do run into an inorganic material that does have an odor, then the material is probably something human-made, and the odor was most likely an organic compound placed there by the manufacturers. Our ability to detect odors depends on the amount of molecules available to our olfactory receptors. As I mentioned before, individual receptors respond to different compounds in different ways, but our olfactory system isn't really set up to detect specific compounds — instead, it reacts to all the various odorous stimuli all mixed together.

Also, because our brains tend to ignore continuous stimuli, we lose the ability to detect odors after being around them for a while. This is why you generally have to ask somebody else if you want to find out what your own body odor smells like. Now that we know that smells are carried by odorous gas molecules through the air, we can at least take a stab at working out the speed of smell.

At the most basic level, particles tend to move from areas of high concentration to areas of low concentration until equilibrium is reached - this is known as diffusion.

This is the basic driving force behind the movement of all odorous compounds and, thus, the fundamental determinant of the speed of smell. Unfortunately, that doesn't tell us very much. In order to get to any single speed of smell, even just one that describes a particular compound, you need to know the temperature, the air pressure, and whether there's any external movement of the air such as, you know, wind. As we discussed earlier, there are similar factors in play that affect the precise speeds of light and sound.

But the differences in the speed of light are insignificant, and we generally only care about the speed of sound in air as opposed to other mediums, so we can get away with ignoring these complicating factors and thinking of single values for the speeds of light and sound. And that's where, in so many ways, the speed of smell falls down. Every smell is going to have a different speed depending on its own particular density, and then there are still so many external factors to control for that you can't really hope to come up with any particular value.

We know that, thanks to diffusion, and odorous molecule will keep on diffusing until equilibrium is reached, meaning it's more or less evenly spread out in the air. Before that, the concentration of the odor will drop below the minimum threshold at which our noses can even detect its presence. And that's the final word on the speed of smell No, it isn't, because there's still one other way that we might think of the speed of smell.