|MadSci Network: Biochemistry|
Well, I still haven't been cooking with onions yet, but when I do, I'll try your idea as best I can. First, you seem to have made an interesting observation. I'm not entirely sure I understand what you mean, whether you are talking about removing the smell from your hands or the knife or whatever. But once you've made an observation you need to do an experiment. First you need a control to compare the experiment to. I presume that would be to have no running water. Then you need to measure the effect. That's hard with smell. In order to measure it objectively you can't have your feelings interfere with how you perceive the smell yourself. The best way to do that is to have someone else who is "blindfolded" and who doesn't know if the knife blade or whatever has been under the cold running water. Only if their findings consistently agree with what you think should be happening, will I believe that something reproducible and scientific is happening. Part Two: Odor is when, as you breathe in, the air is pulled through the nose. Special sensory cells (of which there are many different types) react to different molecules in the air when these molecules hit the surface of these cells. Then they "react" to a new molecule by sending a message through nerve to your brain which makes your brain feel and think "I smell something". Although air doesn't have a smell by itself, lots of other molecules trigger a "smell" message. Onions have small oily sulfur containing chemicals in them which are very strong at making a smell response. When you cut open an onion, the cells of the onion a sliced open and its insides are exposed. The whole thing is so rough (from the cells point of view) that you can see how lots of these molecules are broadcast into the air where they float around waiting to pulled up into your nose. And then you'll say, "I smell an onion". Some of these molecules actually irritate the moist cells of you nose and eyes, which if you get enough of them will make you cry! These oily smelly onion molecules can dissolve in water. So running water can wash them away and then you won't smell them as much. Also, water just rushing by in air will pull the odor molecules from out of the air which will reduce the smell. Power plants burning coal also produce different types of sulfur containing molecules which are bad to breathe and cause pollution. So the exhaust from a power plant can sent through giant chambers with running water in them to "scrub" the air clean. This "scrubbing" soaks up all those bad pollution molecules. You may be using your kitchen sink as an onion smell scrubber. If the onion touches your skin, the irritating molecules can pass through your skin and travel through your blood stream and then you'll feel their effect on your eyes. If your hand is under water or under running water, then these molecules will tend to be carried away by the water and won't be able to get into your skin. I don't know what you'd call it except that the molecules are being "diluted out" or "carried away" by water. Again, I'm not exactly sure what you're talking about, but there are some of the things which may be going on.
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