Plasma is the fourth state of matter. It is created when a gas is heated or placed in a strong magnetic field, where its atoms and molecules release electrons and become ionized, causing it to glow. This week's viewer question comes from Omar A. in Jordan.
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00:00 What state of matter is plasma?
00:07 The philosophers of ancient Greece recognized four different elements.
00:14 The solid earth, the liquid water, the gaseous air, and the burning fire.
00:26 Our sun is much hotter than earthly fire. It's made up mostly of matter that's in what's
00:31 called a plasma state.
00:34 Over 99% of the matter we're able to see in space is in a plasma state. But plasma also
00:40 forms on earth, when lightning strikes, for instance, or when auroras appear.
00:47 Plasma is also known as the fourth state of matter. Everyone knows the other three from
00:53 everyday life.
00:55 Ice is the solid state of H2O. If we add energy to the ice, for example in the form
01:01 of heat, then it melts and turns into a liquid, water. If we turn up the heat even more, the
01:08 liquid becomes a gas, water vapor. If you heat that vapor to extreme temperatures, it
01:15 turns into a plasma.
01:17 During the process, atoms and molecules transform into electrically charged ions. They release
01:25 negatively charged electrons that zip around quickly between the particles. This so-called
01:31 ionization makes plasma electrically conductive and also makes it glow.
01:38 This is why plasma often plays a role in lighting technology. In medicine, on the other hand,
01:46 plasma can help heal chronic wounds. When turned on aggressive microbes, it kills them
01:51 and at the same time stimulates cells to grow.
01:55 In space travel, plasma is used in ion thrusters. They're an efficient way to cover long distances
02:02 on little fuel.
02:05 Plasma can also be used to cut even the hardest metals quickly and precisely, while future
02:10 fusion reactors might employ it when generating energy.
02:15 (upbeat music)