The paper clip is more dense than water but can rest on the surface of the water because of the water's surface tension. Evidence of water's surface tension can be seen where the water strider's legs ...

Surface tension measurements were made on a series of aqueous solutions of potassium hydroxide ranging in concentration from 6.5 to 41.2 weight per cent potassium hydroxide.

The surface composition, as inferred from the surface tension, also plays an important role in the equilibrium size of small aerosol droplets (<150 nm diameter) and the activation of cloud ...