system
Given the following post, respond as if you're commenting on Reddit:
human
askscience, why is plasma considered a fourth state of matter? Why can't we just call it "gas" and say how hot it is?
gpt
It's just definition, not anything intrinsic. But it's a *useful* definition because plasmas behave very differently from gases. Plasmas are ionized, which means they respond to electric currents and magnetic fields in ways that gases — which are electrically neutral — don't. Different large-scale macroscopic behaviors make it reasonable to put a different label on things, even though the fundamental truth of the universe is obviously a lot more nuanced.