THE FOURTH STATE of MATTER
PLASMA - - -not just for TVs
SOLID, LIQUID, GAS, AND....... WHAT?
Quick, what’s the fourth state of matter?
This should be as easy as naming John, Paul, George, and Ringo.
Ninety-nine percent of the universe is made of it. The Earth is surrounded by
it. The aurora borealis is a lovely example of it. So is lightning. Even the sun is made of it. “Fire!” you guess, and you’re on the right track, at least.
THE ANSWER IS PLASMA.
Perhaps an anticlimax? Plasma is a gas in which atoms have been ionized —that is to say, stripped of electrons. Because of that, plasma has magnetic and electric fields that move around rambunctiously and unpredictably, altering their environment. As the environment changes, so does the plasma—a continuous dance of action and reaction. It’s usually hot, but it can also be cold. “Plasma has a life of its own,” says Walter Gekelman, who researches the stuff in an enormous basement laboratory at UCLA.
IONIZED GAS WAS FIRST DESCRIBED IN THE LATE 1800S BY AN ENGLISHMAN NAMED SIR WILLIAM CROOKES, but not until 1928 did an American chemist, Irving Langmuir, name it plasma. Names aside, Gekelman and other scientists are still trying to understand the fundamental reasons why it behaves the way it does. Maybe that’s why plasma has never had the respect that a full-fledged state of matter ought to have. But that’s likely to change, and not just because of plasma-screen TV. (Not that a plasma screen isn’t a pretty nice addition to the family room: Its weakly ionized cold plasma eliminates the ponderous cathoderay-tube technology that makes your TV too big for the shelf you’d like
to keep it on.)
Plasma could be key to new energy sources. The core of the sun is a plasma denser than lead and SO hot—15 million degrees C —that atomic nuclei fuse together there, releasing a huge amount of energy. Everyone knows that for many decades scientists have tried to replicate the sun’s nuclear fusion feat. They’ve built reactors that use plasmas heated to tremendous temperatures, but so far they haven’t been able to get more energy out than they’ve put in. They need a bigger reactor.
Still, “plasma’s uses are multiplying like crazy,” says Gekclman. The rockets of the future may be powered by thin beams of highly accelerated plasma. Cold plasma is essential to many industrial operations: For example, it’s used to etch the grooves that carry information on the surfaces of computer chips. Mounir Laroussi, a physicist at Old Dominion University, has developed a sort of pencil that shoots out a small stream of cold plasma. It can sterilize equipment that would normally be damaged by heat. Such a device might even he used to disinfect a flesh wound, killing bacteria by blowing out their cell walls without harming other cells. Plasma makes the fibers in disposable diapers more absorbent and makes ink lettering stick to plastic potato-chip bags.
Laroussi says that when he was in high school he never heard about plasma. But there’s so much of it in the universe, and it has so many potential uses, that there will come a day, he predicts, when everyone knows that it’s the fourth state of matter.
Washington Post - Staff Writer.
NATIONAL GEOGRAPHIC Magazine
Church of the Science of God
La Jolla, California 92038-3131
© Church of the Science of GOD, 1993