How is everything in the air? Atoms make up materials. In solids and liquids, electrical forces hold these atoms together. At any temperature, each of these atoms is randomly moving only slightly. When an atom moves slightly closer to a neighbor, the neighbor repels it. And, now the farther neighbor on the other side attracts it. Thus, the attraction and repulsion forces confine the atom to a small volume. This volume determines the density of the material.
At the surface, the atoms feel the electrical forces only on one side. The attractive forces on just one side tether these atoms. The scenario is similar to a flying kite held by the string. A slightly stronger wind could blow the kite off its tether. Much in the same way, the atoms are randomly blown off the surface or vaporized.
As temperature increases, the random motion of atoms gets stronger. Thus, more atoms vaporize. At boiling temperature, the vapor concentration equals that of the surrounding air. Higher boiling materials have stronger attractive forces. Hence, they have fewer atoms in the air. Nevertheless, everything is constantly evaporating. But, the evaporation rate is just too small to notice in solids.
Author: Dr. Gururaj Naik.
LinkedIn Profile: Visit here.
