Solids can very easily be distinguished from liquids by their definite shape, considerable mechanical strength, and rigidity. There are many different types of solids. Some are soft and others are hard. Some are rigid and others are flexible. The atoms and molecules of solids are held together by pulling forces called bonds.
The atoms in solids are held together by interatomic forces. The average location of the atoms in a lattice does not change with time. Since the atoms are almost lacking in mobility, their kinetic energy is negligibly small. It is this lack of mobility which makes a solid rigid.