The Three States and the Kinetic Molecular Theory
≈ 25 minThe kinetic molecular theory (KMT) explains matter by saying: all matter is made of tiny particles that are always moving, and the amount of movement and spacing decides the state.
| State | Arrangement | Movement | Shape & volume |
|---|---|---|---|
| Solid | packed, ordered, touching | vibrate in place | fixed shape, fixed volume |
| Liquid | close but disordered | slide past each other | takes container's shape, fixed volume |
| Gas | far apart, random | move fast in all directions | fills the container, no fixed volume |
As you heat matter, the particles gain kinetic energy and move more. Enough heat overcomes the forces holding them together, and the substance changes state — solid → liquid → gas.
In which state are the particles furthest apart and moving fastest?
A liquid has a fixed volume but takes the shape of its container. Why?
According to the kinetic molecular theory, what kind of energy do particles gain when a substance is heated? (one word)