Introduction to Plasma

Liquid, solid, gas. Most high school graduates will be able to tell you at least a bit about each of these three states of matter, as they’re all fairly common occurrences in the natural world. We drink liquids, we eat solids, we inhale gases. Simple enough, right?

Now ask those same graduates about the fourth state of matter. Most won’t know a thing. Some might even think there isn’t a fourth state of matter. Yet there is, and that state is known as plasma – and it may come as a surprise to know that plasma is, by far, the most prevalent state of matter.

Plasma is everywhere, yet it seldom ever touches the earth. It’s a substance that surrounds at every minute of every day, and comprises more than 99 percent of all matter in the universe – yet it’s not something that’s natural to Earth. At the same time, though, we can see the product of plasma virtually every day of the year. Why is this?

Plasma is a “conductive assembl(y) of charged particles, neutrals and fields that exhibit(s) collective effects”. It’s matter, similar to a gas, in which a portion of the particles are ionized from large amounts of heat, far beyond that found in a gas. Electrons are lost, and the resulting matter has charged particles, positive ions and negative electrons. It consequently can conducts electricity and is affected by electrical fields, making plasma useful in a variety of everyday, man-made devices. Plasma can be both extremely hot and relatively cool, leading to a variety of different forms of the substance, though the density and coolness of matter on our planet is typically not enough to sustain plasma in a normal state.

Though it’s not the best-known scientific term around, plasma was discovered well over 100 years ago when it was observed by Sir William Crookes in 1879. It was not identified as a new state of matter until 1897 by Sir J.J. Thomson, however, and the name ‘plasma’ is attributed to Irving Langmuir in 1928. The name may have been chosen thanks to plasma’s appearance, which closely resembles that of blood plasma.

Plasma is, normally, found in space. The empty space surrounding the planet, for example, is composed of small traces of plasma, accounting for the mass amounts of plasma in the universe. More obvious than that, though, is our sun: all stars are composed almost entirely of plasma rather than normal gases. That said, however, plasma appears in several earth-bound, familiar forms as well:

– Fire

– Lightning and ball lightning

– St. Elmo’s Fire

– The Aurora Borealis

As noted earlier, plasma can also be used in a variety of man-made products, and has been growing in popularity in recent years thanks to its ability to conduct electricity. Plasma can be found in, or as a result of, the following artificial sources:

– Plasma TVs

– Neon signs

– Fluorescent lighting

– Arc welders

– Plasma torches

– Tesla coils

– Rocket exhaust

Because plasma is often associated with extreme heat, contact with this form of matter can be extremely dangerous, and obviously in some cases, fatal. However, plasma’s generally artificial presence on Earth, and its controlled nature, helps ensure that it does not become a threat. Moreover, natural plasma will turn into a neutral gas if it is not properly maintained, which typically happens in Earth’s atmosphere.