States of Matter Using the Kinetic Particle Model

The kinetic particle model explains the physical properties of solids, liquids, and gases based on:

• Arrangement: Particles in solids are tightly packed in a fixed, regular pattern; in liquids, they are close but randomly arranged; in gases, they are far apart and randomly arranged.
• Motion: Particles in solids vibrate about fixed positions; in liquids, they slide past each other; in gases, they move rapidly in all directions.
• Forces and Distances: Strong forces and short distances in solids; weaker forces and slightly greater distances in liquids; negligible forces and large distances in gases.

Brownian Motion and Molecular Movement

Brownian motion refers to the erratic, random movement of tiny particles (like smoke or pollen) suspended in a fluid. This is observed under a microscope.

It provides evidence for:

• The existence of tiny, invisible molecules in a liquid or gas.
• The random and constant movement of these molecules that collide with the suspended particles, causing them to move unpredictably.