Plasma
A state of matter consisting of a hot, electrically conducting mixture of ions and free electrons.
Unit
K
In depth
Heating a gas strongly enough strips electrons from atoms, producing an overall neutral but ionised medium that responds strongly to electric and magnetic fields. Plasma is by far the most abundant form of ordinary matter in the universe, since stars are made of it, though it is rare on Earth's surface.
Examples in the real world
Lightning, the interior of a neon sign, a welding arc, and the entire body of the Sun.