FtG (12/22/82)
The responses to my teabag question were basically depressing with few exceptions. In general the responses fell into four categories: 1. Redundant (4) These people suggested explanations that I had already listed (something that happens too often on the net- READ BEFORE YOU LEAP!) or Suggested PV=nRT, which is an APPROXIMATION. The figure of .0038... is from the CRC manual and is correct for atmos. pressure from 0 to 100 C. I know what I'm talking about so less accurate information doesn't help. 2. Useless (1) No real information content. 3. Irrellevant (3). People sure send mail for the oddest reasons. Try dev.null next time. 4. Helpful (2). Two people (err, three people, two messages. Hello Aloha!) gave facts and insights. None suggested a fifth explanation for the phenomenon, which I think makes the others more viable. I overestimated the size of the bubble, mentally projecting it into the tea, when in fact the bubble is flat on the bottom and barely goes under the surface. Hence there is really less air in the bag than it appears- a kind of optical illusion. This coupled with the fact pointed out by one of the correspondents in group 4 suggests that water vapour mixed with air is all that is neccessary. The key point is that once the vapour mixes with the leftover air, it takes quite a while for it to condense. Thankyou for your time and trouble FtG, rochester.
drabik (12/22/82)
Come on, guys. Before you pour water over the teabag, there is a certain volume of air interleaved with the volume occupied by the leaves. When you pour the water, the air is displaced from the leaves by the water which is absorbed through capillary action and forms the bubble. Schluss. Tim Drabik BTL Indian Hill
lew (12/22/82)
The teabag problem provides an excellent opportunity for the conception and execution of a critical experiment. Remember the story about the philosophers trying to figure out how many teeth a horse has, but disdaining to count them? It is easier to laugh at this story than to learn from it. Nevertheless, we are entitled to our opinions, and I opine that Tim Drabik's explanation is incorrect. I believe this explanation ( water displaces air ) could be refuted or verified by using cold water instead of hot. Distinguishing the effects of air expansion from those of water vapor production presents a nicer problem. I personally am content that it must be the water vapor. My teabags stay inflated only so long as I continue to pour hot water on them. I take this to mean that the inflation depends on the continuous production of water vapor at the bag surface. Lew Mammel, Jr. ihuxr!lew