A radio is an electronic device that pays audio. It is used as light entertainment, listening to music, news, important announcements and advertisement messages.

The invention of radio is debated. Guglielmo Marconi is often credited with the invention but the physics of radio is based on work by Nikola Tesla. In the early year after its invention, the radio was found to be very useful during maritime. They were used to send telegraphic messages of Morse Code between ships and land.

So how the heck does it work?

Radio waves, like visible light, infrared, ultraviolet, X-rays and gamma rays, are electromagnetic waves. A transmitter at the radio station converts sound waves into electromagnetic waves, which are then encoded onto an electromagnetic wave in the radio frequency range which is broadcast. Radios contain an antenna to detect this transmitted signal, a tuner to pick out the desired frequency, a demodulator to extract the original sound wave from the transmitted signal, and an amplifier which sends the signal to the speakers. The speakers convert the electrical signal into physical vibrations (sound).

According to the CIA World Factbook, there are about 44,000 Radio stations worldwide. Radio Scotland is the most popular radio station in this country, with around 975000 regular listeners. Its average fan tunes in eight hours a week.