Science
What is State of Matter?
A state of matter is one of the distinct forms that matter can take — most commonly solid, liquid, or gas. Which state something is in depends on how much energy its particles have and how tightly they're held together. Adding or removing heat can switch matter from one state to another.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains state of matter.
Key things to understand
- 1The three everyday states are solid, liquid, and gas; plasma is a fourth, common in stars and lightning.
- 2What differs between states is how the particles are arranged and how fast they move — not the particles themselves.
- 3In a solid, particles are packed tightly and vibrate in place; in a liquid they're close but can slide; in a gas they're far apart and move freely.
- 4Adding heat gives particles more energy, which can melt a solid or boil a liquid; removing heat reverses it.
- 5The same substance can exist in different states — water is ice, liquid water, or steam.
Frequently asked questions
- What are the states of matter?
- The three everyday states are solid, liquid, and gas. A fourth, plasma, occurs at very high energies (like in stars and lightning). They differ in how their particles are arranged and move.
- What decides which state matter is in?
- Mainly energy (temperature) and pressure. More heat gives particles enough energy to break free, pushing matter from solid → liquid → gas; cooling does the reverse.
- Can matter change state?
- Yes. Adding or removing heat changes the state — for example melting (solid to liquid), boiling (liquid to gas), and freezing (liquid to solid).