Essay on The Electromagnetic Spectrum

1895 Words 8 Pages
The Electromagnetic Spectrum

The electromagnetic spectrum is the collective name for all types of
radiation. Radiation is energy that travels around in waves. The
electromagnetic spectrum goes from the waves with the lowest energy to
those with the highest energy.


Radio Waves

[IMAGE]

Radio waves have the longest wavelengths in the electromagnetic
spectrum. They can be from as long as a football to as long as a
football pitches. Radio waves carry signals from devices from one
place to another invisibly through the air.

Radio waves are used for many different jobs:

b In Medicine - radio waves are used to transmit the pattern of a
heartbeat through a monitor at a patient's home
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[IMAGE]Celestial bodies that transmit radio waves: Karl Jansky was the
first to determine that radio emission from the heavens could be
detected. At the Bell Laboratory in 1932, Jansky built a rotating
antenna, and attempted to investigate the source of the short wave
interference. He found that there was a hiss-type static that was the
most intense when the antenna was directed downward towards the centre
of the galaxy. He found that the galaxy itself was an intense source
of radio radiation. Some celestial bodies that emit radio waves that
sound like static, are Venus and Jupiter. These sounds are caused by
terrestrial thunderstorms.

Radio telescopes look toward the heavens at planets and comets, giant
clouds of gas and dust, and stars and galaxies. By studying the radio
waves originating from these sources, astronomers can learn about
their composition, structure, and motion. Radio astronomy has the
advantage that sunlight, clouds, and rain don't affect observations.


[IMAGE]Microwaves

Microwaves are measured in centimetres because they are so big. They
range in size but it is the larger ones that we use to heat or food in
a microwave oven.

Microwaves are good for transmitting information from one place to
another because microwave energy can penetrate haze, light rain and
snow, clouds, and smoke.

[IMAGE]Shorter microwaves are used in remote…

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