Earth Science – Earth’s Waters Practice Test

Surface tension is the property that creates water’s skin. It comes from the cohesive forces between water molecules, especially hydrogen bonds, which pull the molecules at the surface inward toward the bulk. Because surface molecules have fewer neighbors to attract to, they experience a net inward force, forming a tight, elastic-like layer at the surface. This “skin” lets water form droplets, supports lightweight items on the surface, and gives water its characteristic surface behavior. The other properties—boiling point, viscosity, and density—describe temperature for phase change, flow resistance, and mass per volume, but they don’t produce the surface film that water’s skin comes from.