Matter makes up everything around us — from the air we breathe to the stars in the sky. But did you know it transforms between distinct states? In this guide, we’ll explore the fundamental states of matter (solid, liquid, and gas), their properties, real-world examples, and how they shape our universe. Perfect for students, educators, or science enthusiasts!
What Are the States of Matter?
States of matter describe how particles arrange and behave under different temperatures and pressures. The three primary states are:
The Solid State
The molecules, atoms, and ions in the solid state are held in close proximity by intermolecular, interatomic, or ionic forces. The atoms in the solid can oscillate only about fixed positions. As the temperature of a solid substance is raised, the atoms acquire sufficient energy to disrupt the ordered arrangement of the lattice and pass into the liquid form.
Finally, when sufficient energy is supplied, the atoms or molecules pass into the gaseous state. Solids with high vapor pressures, such as iodine and camphor, can pass directly from the solid to the gaseous state without melting at roomtemperature. Thisprocessis knownassublimation,and the reverse process, that is, condensation to the solid state, may be referred to as deposition.
The Liquid State
When a gas is cooled, it loses some of its kinetic energy in the form of heat, and the velocity of the molecules decreases. If pressure is applied to the gas, the molecules are brought within the sphere of the van der Waals interaction forces and pass into the liquid state. Because of these forces, liquids are considerably denser than gases and occupy a definite volume. The transitions from a gas to a liquid and from a liquid to a solid depend not only on the temperature but also on the pressure to which the substance is subjected.
The Gaseous State
Owing to vigorous and rapid motion and resultant collisions, gas molecules travel in random paths and collide not only with one another but also with the walls of the container in which they are confined. Hence, they exert a pressure— a force per unit area—expressed in dynes/cm2.
Reference:
- Sinko, P. (2011). Martin’s Physical Pharmacy and Pharmaceutical Sciences. Baltimore, : Lippincott Williams & Wilkins, a Wolters Kluwer business.
