Capillary action is the movement of water within the spaces of a porous material, like the fibers of a paper towel. This movement is driven by adhesion (attraction between water and the paper towel fibers) and surface tension (water molecules sticking together). The water moves upward because it adheres strongly to the walls of the small gaps between the paper towel fibers, effectively "pulling" itself up against gravity. #science #education #physics #chemistry #scienceisfun #scienceteacher #hei