Why Water Drops and Needles Float

Surface tension helps explain why water forms drops, supports small objects, and moves in thin tubes. It is a property of fluids at the boundary between a liquid and a gas, or between two immiscible liquids. At the surface, molecules are pulled inward by neighboring molecules. That inward pull makes the surface act a little ...

A steel needle or a razor blade can float on water if placed gently due to surface tension, which arises at the interface between a liquid and a gas or two liquids that do not mix.

The surface tension makes the liquid surface behave like a stretched elastic membrane, thereby supporting the object.

Surface tension results from cohes...