Surface tension is a surface stress that arises from the interactions between molecules at the interface of a liquid, influenced by the curvature of that interface. It is not a vector force but rather a balance of forces, particularly at a three-phase contact line, where Young's equation applies. Molecules at the surface experience different forces compared to those in the bulk, leading to attraction among surface molecules and contributing to surface tension. This phenomenon prevents surface molecules from being drawn into the liquid, maintaining stability and minimizing potential energy. Ultimately, surface tension plays a crucial role in the behavior of liquids and their interactions with surrounding environments.