Where do the lovely cooking aromas in your kitchen go?

Readers answer other readers' questions on subjects ranging from trivial flights of fancy to profound scientific conceptsThose lovely aromas in the kitchen – where do they go?They condense into a sticky film on the walls and ceiling, and if you don't wash it off, it hardens into a rancid varnish that is tougher than epoxy resin.Luce Gilmore, Cambridge They flood into my flat from the neighbour's at 2.15am, strong enough to wake me up and give me a raging appetite.IvanTigerThose lovely aromas, of frying onions, for example, are the result of molecules present in the onion leaving the cooking food and moving randomly through the air until a few of them happen to enter your nostrils and are detected by your odour receptors.Molecules are always jiggling about, but, in the case of most solids, the majority of the molecules don't have sufficient speed (energy) to escape the surface. However, you can smell cheese or garlic if your nose is close, as the odours are particularly intense and the few escaping molecules have not been much diluted by air molecules.Heating increases the speed of the molecules and hence increases the number escaping. Very few of the escaping molecules enter your nose. Those that don't will gradually slow down, buffeted by the very much larger number of air molecules. Eventually they will collide with the walls, ceiling, floor, other parts of your body and settle there, although a few may escape through open doors and windows. So mostly they end up coa...

Source: Guardian Unlimited Science - February 20, 2013 Category: Science Tags: The Guardian World news Food & drink Books Letters Features Life and style Religion Science Source Type: news