State Of Matter - GCSE Physics Definition

The term "State of Matter" refers to the different forms that substances can take based on their physical properties and the energy of the particles they are made of. The most common states of matter are solid, liquid, and gas. In a solid, particles are closely packed together and have a fixed shape. In a liquid, particles are still close but can move past each other, giving the liquid a definite volume but no fixed shape. In a gas, particles move freely and quickly, filling any container they are in, which gives gases neither a fixed shape nor a fixed volume. Understanding the states of matter helps explain how substances change from one form to another, like when ice melts into water.