Question

Why are solids rigid?

Answer 1

Hint:Rigidity is defined as the property exhibited by the solid to change in its shape. That is when an external force is applied to the solid material, there won’t be any change in the shape.

Complete step by step answer:
> Let us see what solids are actually?
Solids are hard substances, because of the molecules which are packed together. It retains its shape and density when not confined. The atoms or molecules of matter in the solid state are generally compressed as tightly due to their repulsive forces among them .
> What are crystalline solids?
Some solids tend to fracture along defined surfaces that have a characteristic shape depending on the arrangement and the forces among them. Other solids , known as amorphous solids, lack any apparent crystalline structure.
> Now, let us understand about amorphous solids.
Amorphous solids are rigid, but they lack repeated order of constituting particles in their structure. Amorphous solids lack a characteristic geometry, along all axes , having wide ranges over which they melt, and break to form curved shapes.
> Let us understand why solids are rigid.
Solids are rigid, because of the relative stronger intermolecular attractions between them as compared to solids and liquids. Those all forces are electrostatic in nature. By supplying heat the increased kinetic energy of the molecules by which we can change the shape or volume of the substance. Here electrostatic forces refers to the dipole forces, hydrogen bonding forces and induced dipole forces etc..

Note: Gas vibrates and moves freely at high speeds, liquids vibrate (move) and slide each other but solids vibrate and generally do not move from place to place because gaseous molecules are bonded by weaker interparticle attraction while solid are bonded by stronger interparticle attractions.