Atmosphere/Hydrosphere Project
Properties of Water
Surface Tension
Surface tension is the property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules. Consequently, the molecules on the surface adhere more strongly to that above the surface. This forms a surface "film" which makes it more difficult to move an object through the surface than to move it when it is completely submersed. This occurs in the water cycle during the precipitation stage when raindrops fall.
Expansion upon Freezing
When water freezes, it moves apart because the force that holds molecules in its liquid state is different from the force that holds molceules together in its solid state. In addition, the force that is holding the water molcules together in the liquid state is actually stronger than in the solid state. This can occur in the water cycle during the precipitation stage, when sleet falls.