Daisy, (sniff, sniff)

The matter we smell comes from evaporated liquid in its gaseous form. When we spritz some type of fragrance into the air and if we look closely enough we can see the liquid falling down, but what we actually smell are the molecules that have evaporated and gone into our nose and into our odorant receptors. These receptors come in many shapes and sizes and when we smell, its because the molecules have met the same characteristics and size of the receptor. While we have about 1000 different receptors dogs have many more than us, thus being far better at catching odors than us. Interestingly enough, these receptors are also connected to other parts of the brain which is why sometimes a certain smell can take us back to a time that we lived long ago-it has the power to make us recall old memories. Today, scientists are trying to understand the connection between a sexual partner and pheromones.

Pheromones: n. A chemical secreted by an animal, especially an insect, that influences the behavior or development of others of the same species, often functioning as an attractant of the opposite sex.

I thought it was really interesting that we are really sensitive to smell that is penetrable with water because our own receptors have a “thin layer” of water. Thus, gases that cannot penetrate water are not easily picked up by our noses.

The book states that scientists are working on artificial noses. These could potentially help distinguish other smells that are not so easily picked up by a human nose.

Baird, Colin, Chemistry in Your Life, 2nd Edition, pgs 43,44, Freeman, NY, 2006

"pheromone." The American Heritage® Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company, 2004. Answers.com 18 Jan. 2008. http://www.answers.com/topic/pheromone