What Is a Solid?

The area of chemistry and physics that studies matter—the substances of which the universe is composed—is known as physical science. Within physical science, there are three main states, or phases, of matter: solid, liquid, and gas. Today, we are exploring solids.

What Are Solids?

Solids, one of the three main states of matter, are composed of particles that are packed together. The particles, called molecules, are packed in different arrangements depending on the type of solid. These arrangements determine the properties of the respective solids, such as their shape and hardness.

The Particles in a Solid

The particles in a solid are generally in fixed positions, and it is this fixed arrangement of the particles that gives solids their structure. Unlike gas particles, solid particles are held in place by forces, such as intermolecular forces or electrostatic forces, that are called bonding forces. One of the most common types of solids are molecular solids, which are composed of molecules held together by strong intermolecular forces. Also common are ionic solids, which are composed of atoms held together by electrostatic forces.

Solids interact with the environment using different properties. First, solids have a definite shape, meaning they cannot be changed without breaking or melting the solid. Solids also have a definite volume, meaning they occupy a certain space, no matter the pressure applied to them. Lastly, solids are relatively incompressible, meaning they cannot be easily compressed or reduced in size.

In summary, solids are one of the three main states of matter, and are composed of fixed particles that are held in place by bonding forces. Solids have a definite shape, volume, and cannot be easily compressed.