Atoms are very small. In a single drop of sea water there are fifty billion atoms of gold. Enough gold that every person in the world could have five atoms of gold from that one drop. And yet you would have to distill two thousands tons of such water to get enough to see with the naked eye. Atoms, or combinations of atoms called molecules, are continually in motion, and that motion is what we call heat.
Atoms make up the balmy air of a summer day.
In that calm air the atoms are traveling at speeds three times greater than that of a bullet leaving the muzzle of a rifle. The atoms collide with their neighboring atoms and molecules over five thousand million times a second. Even then they quiver inside. Atoms, small as they are, have an incredibly dense nucleus surrounded by clouds of electrons. Again, to give you some idea of proportion, if you were to enlarge a single atom to the size of Yankee stadium, the tiny dense nucleus would be the size of a mosquito over second base.