The Mudcat Café TM
Thread #59418   Message #2195353
Posted By: Amos
16-Nov-07 - 12:17 PM
Thread Name: BS: The Mother of all BS threads
Subject: RE: BS: The Mother of all BS threads
The inherent surface tension of water is the same, as Janie speculates. The side away from the air may be up against something more irregular, like a tabletop, which at a molecular level will have lots of peaks and valleys. It will therefore have a non-uniform pressure on various points along the water boundary, and these will change the amount of additional force needed to break the surface tension. The static force between gravity and the irregular structure when the water is at rest counteracts the surface tension in a way not experienced by the air-boundary side. There may be even something else going on right at the perimeter where the air, water, and tabletop meet.