How was radio invented?

To answer this, we need to go quite far back in time! One of the oldest methods of getting a message across was smoke signals, as you may have seen American Indians use in a film.

One puff for A… Two puffs for B… You get the idea.

For hundreds of years people would use puffs of smoke to send coded messages. Later on, they used other ways of sending signals – like flags – that’s called Semaphore!

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To help the most number of people see your message, it was good to be high up (like on top of a hill) so that people could see the signals wherever they were… which was great… unless it rains… or is dark… or the person watching is asleep!

Over 200 years ago, clever clogs figured out that they could send coded messages using electricity over cables.

At first they used them to send messages around the country but by 1860 they were sending messages between countries on submarine cables like these! They called it electrical telegraphy.

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The first cables were very basic. They could only send a pulse which would just about be detected at the other end. They used systems such as morse code to spell out messages.

But it took time to send messages – not great if you have lots to say – and it could definitely not send music.

Luckily scientists found another, even better way to carry messages. One of those scientists was called Hertz.

People were beginning to understand that there were energy waves all around us that we can’t see. Hertz proved that they existed in an experiment – he sent electromagnetic waves through the air by creating sparks, which then created a spark on a ring that wasn’t even touching it.

Before then people didn’t really understand that these waves even existed – far less that they could be created.

Electromagnetic waves are everywhere – from the sun’s heat to colours in a rainbow and X Rays. They’re all around us like ripples on a pond! It must have been really exciting to realise that they could be created!

It wasn’t long before other engineers discovered that if the waves were moving then there could be a way to carry stuff with it. Roll forward to 1920 and Marconi was inventing a way of sending signals over those energy waves – and that led to the very first radio!