Electromagnetic (EM) energy is all around us. Electromagnetic waves can travel a long distance. Waves have three main aspects – wave length, amplitude and frequency.
EM radiation comes in lots of different frequencies which are places on a scale called the EM spectrum.
Radio waves were discovered by Heinrich Hertz in 1886. The frequencies of waves are measured in Hertz.
You could send and receive radio signals on the Moon, but not in the sea. Radio waves travel easily through space, but only a few meters in water.
Radio waves are transmitted (sent) by tall masts and received by an arial on your TV or radio. See how radio works in my next post.
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