Tech.CONNECT
Plasma
A gas that has electricity running through it is called
plasma. Plasma is sometimes considered to be a fourth
state of matter. It is found mainly in the stars and nebulas
within our universe.
Figure 2
Neon lights contain plasma.
Figure 1
The northern lights (aurora borealis)
Plasma has fascinated
people for thousands of years.
The northern lights (aurora
borealis) are an example of
plasma in nature (Figure 1). In
ancient times, the Inuit people
believed that the northern
lights were the torches of
spirits guiding souls to a land
of happiness and plenty.
Today you can find plasma
in many manufactured items,
such as fluorescent lights, neon
signs (Figure 2), and plasma
balls (Figure 3). The wonder
that you experience when
looking at a plasma ball is like
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Unit B
Chemistry
the wonder the ancient Inuit
people experienced when
looking at the northern lights.
Plasma can even be used
to cut and shape metal.
Plasma cutters (Figure 4) were
developed almost 50 years ago,
during World War II, to help
speed up the process of cutting
and welding metal together to
build airplanes for the war.
Plasma cutters are now used to
shape car frames, to cut large
beams of metal at construction
sites, and are even used by
artists to cut and shape metal
for sculptures.
Figure 3
You can see plasma balls at science
centres or science stores.
Figure 4
A plasma cutter cutting metal.
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Television screens are one
of the newest technologies that
involve plasma. Plasma displays
are not a new invention—
research on plasma displays
dates back a decade or more.
It is only recently, however,
that the technology has been
developed to manufacture
plasma displays at a lower cost.
of transistor-covered glass that
are meshed together. An electric
charge is applied to the gas,
turning it into plasma. This
creates ultraviolet light. The
ultraviolet light illuminates
phosphors that are built into
the glass, creating light that
you can see (Figure 5).
In less scientific terms, think
about one million very small
So how does a plasma
light bulbs arranged between
screen television work? A
plasma screen is quite different two glass plates. The light bulbs
from a regular television screen. are lit by plasma and produce
the spectrum of colour needed
A plasma screen works by
to view an image. The light
suspending an inert (inactive)
bulbs are turned on or off by
gas, such as neon or xenon
[ZEE-non], between two panes the television’s processor.
Why do so many people
wish to have a plasma screen
television? Plasma screen
televisions are so thin and light
that they can be hung on a wall
(Figure 6). This means you can
get a clear view of a plasma
screen from almost any angle
in a room. As well, there is very
little reflection off a plasma
screen. These characteristics
make plasma screen televisions
very desirable.
front glas s
light seen on
TV screen
phosphor
ultraviolet light
glass
Figure 5
Figure 6
How a plasma screen works
Plasma screen televisions are very light and very thin.
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Tech.CONNECT
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