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Unit 6: Sound Page 13
come from some sort of one vibration in one second. The
vibrating particle somewhere. Hertz is named after Heinrich
The reason you can pick up a Rudolf Hertz (1857-1894) a
signal on your radio is because German physicist and professor.
somewhere, maybe miles away, Hertz proved that electricity can be
there is a particle vibrating at some transmitted in electromagnetic
ridiculous speed, creating a wave waves, which travel at the speed of
that moves across distances to light and which possess many
finally vibrate the particles inside other properties of light.
your radio’s antenna. It’s important
to realize, however, that the His experiments with these
particle does not move over that electromagnetic waves led to
distance. The particle that started the development of the wireless
the wave back at the radio station telegraph and the radio.
is still there. It did not move to
A Hertz is a relatively slow
your radio it just vibrated at the
vibration so there are also kilohertz
antenna and started the wave.
(KHz), megahertz (MHz), and
Frequency is a measure of how gigahertz (GHz). A kilohertz is
many times something moves 1000 Hz, a megahertz is 1,000,000
back and forth. A swing, a (a million) Hz, and a gigahertz is
pendulum, a leg of a walking 100,000,000 (one thousand
person all have a frequency. All million) Hz.
those things start at one place,
Some examples of things that
move, and come back to the same
work at these frequencies are
position that they started. This
AM radio stations which broadcast
moving and coming back is one
at KHz, FM stations which
vibration. The faster something
broadcast at MHz, and microwaves
vibrates, the more frequency that
which cook your food with GHz. If
something has.
your radio is “crankin” tunes from
What's a Hertz? radio station 750 AM, a part of
your radio is vibrating at 750,000
Frequency is times a second. If you’re “pumping
measured in wattage into your cottage” with
Hertz. One WSCI at 94.2 on your radio dial, a
Hertz (or Hz part of your radio is vibrating at
for short) is 94,200,000 times a second. If your
radio happens to be green, then
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