why don't odors wear out?

Question

I've noticed that the odor of an object doesn't seem to wear out over time. If odor is simply molecules flying off the object into the air, why don't these molecules "wear out"? If you have something real smelly, like, a perfumed candle, it still seems to smell just as strong, 20 years later. Is the mass of this candle actually decreasing because these molecules are constantly being thrown off? Will the candle actually weigh less after 30 years? etc.

oops - when I said "why don't these molecules "wear out"? " , I meant "RUN out, not wear out". -J

Answer 1

Yes, you are losing mass over time, but you can't say for sure that you aren't gaining stuff back (random things in the air getting absorbed by the candle wax. In either case, the amount of the candle's mass that is from the fragrance molecules is so small that you probably wouldn't be able to measure the difference anyway.

If the perfumed candle was left out in the open air for 20 years, I'd be surprised if it still packed the same odiferous strength as it did 20 years ago. If it was wrapped up in a package, that would be different. If it's in a package, the fragrance molecules wouldn't have anywhere to go and most would end up going back into the candle.

If you are actually using the candle (burning it), then you are exposing parts of the candle now that have never been exposed to air before and thus, it should be releasing fragrance at full strength.

Answer 2

candles will loose their scent over time. it's in aromatic oils that are easily vaporized which give the scent. If they are sealed in a dark room they will evaporate slower and the scent will hang around. The scent will change because some of the oil will stay behind. It will most likely weigh slightly less, but it's hard to say for sure not knowing the containment.

PS: molecules don't wear out. They either change or don't change they don't disappear.