Episode Transcript
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Speaker 1 (00:00):
Welcome to Brainstuff from house stuff works dot com where
smart happens. Hi Am Marshall Brain with today's question, what
is the difference between a fluorescent light and a neon light?
A neon light is the sort of light you see
(00:22):
used in advertising signs. These signs are made of long,
narrow glass tubes, and these tubes are often bent into
all sorts of shapes. The tube of a neon light
can spell out a word, for example. These tubes emit
light in different colors. A fluorescent light, on the other hand,
is most often a long, straight tube that produces white light.
(00:45):
You see fluorescent lights and offices, stores, and some home fixtures.
The idea behind a neon light is simple. Inside the
glass tube, there is a gas like neon, argon or
crypton at low pressure. At both ends of the tube,
there are a metal electrodes. When you apply high voltage
(01:05):
to the electrodes, the neon gas ionizes and electrons flow
through the gas. These electrons excite the neon atoms and
cause them to emit light that we see. Neon emits
red light when energized in this way. Other gases emit
other colors. A fluorescent light works on a similar idea,
but it has an extra step. Inside a fluorescent light
(01:29):
is low pressure mercury vapor. When ionized, mercury vapor emits
ultraviolet light. Human eyes are not sensitive to ultraviolet light,
although human skin is. That's how we get sunburns and
sun tans. Therefore, the inside of a fluorescent light is
coated with a phosphor. A phosphor is a substance that
can accept energy in one form and emit energy in
(01:51):
the form of visible light. In a fluorescent lamp, the
phosphor accepts the energy of ultra violet photons and emits
visible photons. The light we see from a fluorescent tube
is the light given off by this phosphor that coats
the inside of the tube. The light of a neon
tube is the colored light that the neon adams give
(02:12):
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