MadSci Network: Physics |
Thank you for the question, Allison, The reason the wet sponge sticks to the window while the dry sponge does not obviously has something to do with the water. Liquids have a property that helps to hold them together, which is called surface tension. When the sponge gets wet and is stuck against the window, the water forms little bridges between the sponge and the window, which hold the sponge there unless the sponge is too heavy. As the water evaporates away, it will pull the sponge closer to the window until too many of the water bridges break, allowing the sponge to fall unless the sponge has formed other bonds with the window that will keep it from falling.
Try the links in the MadSci Library for more information on Physics.