The following quote comes from this delightful post. Read the quote and tell me if you don't think this is really very cool?!?!??!photo december, 2008... so i wonder how many of my molecules are in this shot taken in my own backyard???
“You exhale roughly a liter of water per day into the atmosphere, and most of this water rains or snows back down again within about a week’s time. The total global precipitation is about 1,000,000,000,000,000 (one quadrillion) times greater than the amount of water you exhale, so your impact on the weather is pretty minor.
But even if you contribute only one quadrillionth of the total water content in a snowflake, that is still about 1,000 molecules. It depends on how well things are mixed in the atmosphere, but there are probably, very roughly, about a thousand of your molecules in every snowflake.”