What does the particle theory of matter state?

The particle theory of matter states that all matter is composed of very small, moving particles. This fundamental principle explains that regardless of the state of matter—solid, liquid, or gas—matter is made up of tiny particles that are in constant motion.

In solids, particles are closely packed and vibrate in place, while in liquids, they are still close but can slide past one another. In gases, the particles are much farther apart and move freely at higher speeds. This movement leads to different properties observed in various states of matter, such as shape and volume.

This concept is essential for understanding changes in states of matter, such as melting or boiling, as it clarifies how energy input can affect the motion of these particles, leading to changes in the physical state. The recognition that all types of matter consist of moving particles helps explain reactions, diffusion, and other interactions in chemistry and physics.