In the physical sciences, a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a second phase, and the humid air is a third phase over the ice and water. The glass of the jar is another separate phase.
A small piece of rapidly melting argon ice shows the transition from solid to liquid.
In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma. Many intermediate states are known to exist, such as liquid crystal, and some states only exist under extreme conditions, such as Bose–Einstein condensates and Fermionic condensates, neutron-degenerate matter, and quark–gluon plasma. For a list of exotic states of matter, see the article List of states of matter.
Bromine in both liquid and gas state, encased inside acrylic in solid state
Helium's orange glow in its plasma state
Artificial plasma produced in air by a Jacob's Ladder. The extremely strong potential difference between the two rods ionize particles in the air, creating a plasma.
SBS block copolymer in TEM