1. Solid: A solid has a definite shape and volume. The particles in a solid are tightly packed together and vibrate in place. Examples: ice, rock, wood.

2. Liquid: A liquid has a definite volume but takes the shape of its container. The particles in a liquid are more loosely packed than in a solid and can move around. Examples: water, oil, mercury.

3. Gas: A gas has no definite shape or volume. The particles in a gas are very loosely packed and can move around freely. Examples: air, oxygen, helium.

4. Plasma: A plasma is a superheated gas in which atoms are stripped of their electrons, creating a mix of ions and free electrons. Plasma has unique properties due to its charged particles, and it's the most common state of matter in the universe. Examples: the sun, lightning, fluorescent lights.

Beyond these four, there are other states of matter:

* Bose-Einstein condensate (BEC): This occurs at extremely low temperatures and involves atoms behaving as a single entity, forming a "superatom".

* Fermionic condensate: Similar to a BEC, but with fermionic particles instead of bosons.

* Supercritical fluid: This state exists beyond the critical point of a substance, where the distinction between liquid and gas phases disappears.

While the four basic states (solid, liquid, gas, plasma) are the most commonly recognized, the study of matter is ongoing, and we are continually discovering new and exotic states.