What are you hearing right now? The surprising answer: light! It is currently bouncing around the world to reach your ears. I’m Jacob Marcus with SHU Discovery Science Center and Planetarium, and this is Discovery Deep Dive.
August 20th is National Radio Day, so what better science could there be for us to talk about than how radio works? It’s the whole reason we’re here. Radio is a simple concept in theory: radio waves are incredibly low frequency light waves, with wavelengths that range from just a millimeter to wider than the planet. By attaching sound information to those light waves and broadcasting them out, radios can transmit and play back sound.
But in practice, it gets more complex. There are two ways to attach sound to a wave: change the amplitude, or how tall the wave is, or the frequency, how fast it moves. There are pros and cons to both: AM radio, changing the amplitude, has a higher range and can transmit signals farther, while FM radio, changing the frequency, is more immune to static.
To get the radio signals to you, radio towers transmit radio waves constantly in all directions at a very specific frequency. When you dial your car to that frequency, your receiver picks up just that frequency, and you get voices and music on demand! But there are thousands of other radio waves being transmitted all around you all the time. Radios, televisions, smartphones, Wi-fi, all function with radio waves.
So the next time you turn on the radio, take a second to think about what’s actually happening. That music, or voice you’re hearing, is being carried to you by invisible waves of light traveling through the world around you. If we could see them as well as we hear them, it would be quite a sight to behold!
