Phases of Matter

Matter exists in four main phases: solid, liquid, gas, and plasma. Solids have a fixed shape and volume, with particles tightly packed together. Liquids maintain a fixed volume but can change shape, with particles that are close but able to flow. Gases have neither a fixed shape nor volume; their particles are far apart and move freely, filling the available space. Plasma, an ionized gas, consists of charged particles and is found in stars, including the sun. These phases can change with temperature and pressure, through processes like melting, boiling, or condensing.