Question: what is plasma?? i don't get it, how can it be in the blood??

Roan Haggar answered on 9 Nov 2020:

Hi! Plasma can mean a couple of different things. In humans and animals, plasma is the liquid part of blood, that carries all of the important stuff like red blood cells around the body. Unfortunately I don’t know very much about this, you’d probably have more luck asking a biologist!
—
In physics, plasma usually means something different. When physicists talk about plasma, they are usually talking about one of the ‘states of matter’. Most materials can either be a solid (when all the atoms/molecules are stuck together, like in ice), a liquid (when the atoms/molecules can move around, like in water) or a gas (when the atoms/molecules aren’t attached to each other at all, like in water vapour or air). We call these ‘states of matter’.
—
Plasma is a fourth state of matter. A plasma is kind of like a gas, but it’s so hot that the atoms themselves have been broken apart! We don’t see plasmas as much as the other three states of matter, but one example is during a thunderstorm — lightning bolts turn the air into a plasma, which causes the bright flash that we see when a lightning bolt strikes.
—
These two things (plasma in the blood, and the plasma state of matter) are completely different, but unfortunately have the same name — science can be a bit confusing like that sometimes! Hope this helps.