To answer this question, you have to understand a few major ideas. Surface Tension Surface tension is the tendency for the surface of a liquid to act like a stretched membrane or piece of rubber. The cohesive forces work to bring the molecules on the interior of the liquid to the exterior surface. T. Capillarity is the interaction between contacting surfaces of a liquid and a solid that distorts the liquid surface from a planar, flat or two-dimensional, shape to concave or convex. Cohesion Cohesion is the attraction of molecules by which the elements of the body are held together.
Water has the highest cohesive force of any liquid except that of mercury.
This makes the water behave as though it were coated with an invisible film. Our body weight is too much for the cohesive forces of the water and we break through the invisible film that the tension creates.