tag:blogger.com,1999:blog-1639738090545138933.post5645224537703279726..comments2024-02-07T10:25:05.837-05:00Comments on Home Climate Analysis: Condensation and ConvectionKevan Hashemihttp://www.blogger.com/profile/11014582378376549743noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-1639738090545138933.post-61851854454022036002011-01-27T14:48:35.785-05:002011-01-27T14:48:35.785-05:00A water molecule condenses when random encounters ...A water molecule condenses when random encounters with other vapor molecules leave it almost stationary and not vibrating, and it just happens to be next to another such stationary and not vibrating water molecule. An existing water droplet is perfect for collecting such stationary vapor molecules.<br /><br />A water molecule evaporates when its liquid neighbors just so happen, by chance, to kick it super-hard so that it shoots out of the liquid and into the adjacent gas. <br /><br />Given any mixture of air and water, there is a certain temperature at which the chance of either happening is equal. We say the gas is <i>saturated</i> with water vapor. Water condenses at the same rate that it evaporates. <br /><br />At a lower temperature, the chance of condensation is greater. The liquid starts to condense. At a higher temperature, the chance of evaporation is greater, and the liquid starts to evaporate.<br /><br />You will note that in order for the water molecule to come to a stand-still, another molecule, say a nitrogen molecule in the air, must receive all its vibrational and translational kinetic energy through the chance encounter.<br /><br />The air heats up during condensation. The liquid water cools down during evaporation.<br /><br />Because condensation is a statistical process, it does not happen instantly. There is nothing wrong with us imagining condensation being delayed until after a rapid expansion of moist air in a cylinder. In that case, the pressure will reach a minimum at the end of the expansion, and rise afterwards when condensation takes place. Indeed, this is how a cloud chamber works. The condensation occurs when a charged particle goes through the super-saturated vapor.Kevan Hashemihttps://www.blogger.com/profile/11014582378376549743noreply@blogger.com