Surface tension is a physical property of liquids that causes their surfaces to behave like a stretched elastic membrane. This phenomenon occurs because molecules at the surface of a liquid experience different forces than those in the bulk. The molecules at the surface are attracted more strongly to each other than to the air above, creating a cohesive force that minimizes the surface area. This effect is why small objects, like a water strider insect, can walk on water without sinking. It also explains why droplets of water form beads on surfaces instead of spreading out flat. Surface tension plays a crucial role in various natural and industrial processes.