Surface tension is the effect of cohesive forces between liquid molecules at the surface of a liquid, which is particularly evident in water due to its strong hydrogen bonding. At the surface, water molecules experience an imbalance of intermolecular forces; they are attracted more to the molecules within the liquid than to the air above. This creates a "skin-like" effect at the surface, causing the liquid to behave as if it has an elastic surface.
To clarify, the surface tension results from water molecules pulling inward (cohesion), which creates a tighter surface layer, rather than pulling outward. The strong cohesive forces among the water molecules are what give rise to surface tension, enabling phenomena such as water droplets forming beads and small objects being able to rest on the surface without sinking.
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