Essay on The Electromagnetic Spectrum

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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


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
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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.


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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