Of state. Contents and Concepts 1. Comparison of Gases, Liquids, and Solids Changes of State

FIGURE 11.18

Demonstration of surface tension of water

A steel pin will float on the surface of water because of surface tension (top). The water surface is depressed and slightly stretched by the pin (bottom), but even more surface would have to be created for the pin to submerge, which takes more energy. The easiest way to float a pin is to place a square of tissue paper, with the pin on top of it, on the prongs of a fork. When the fork is lowered into the water, the tissue and pin float on the surface. The paper soon becomes waterlogged and sinks, leaving the pin floating.