How Radio Waves Work: Invisible Signals All Around You
The invisible highways carrying your music, texts, and WiFi
The invisible highways carrying your music, texts, and WiFi
Radio waves are invisible energy that travels through the air (and space!) at the speed of light. They're how your phone, WiFi, and radio work.
Radio waves are made of oscillating electric and magnetic fields - no air needed!
All radio waves travel at 299,792 km/s - the universal speed limit!
Radio waves are actually light - just with wavelengths too long for our eyes to see.
Frequency is how fast the wave oscillates (cycles per second, measured in Hertz). Wavelength is the distance between peaks. They're inversely related!
More oscillations per second. Shorter wavelengths. WiFi and 5G use high frequencies.
Fewer oscillations per second. Longer wavelengths. AM radio uses low frequencies.
Radio waves are just one part of the electromagnetic spectrum. Click each band to learn more!
The longest wavelengths and lowest frequencies. Used for broadcasting, communication, and WiFi. Wavelengths range from 1mm to 100km!
A plain radio wave carries no information. To send music or voice, we "modulate" (change) the wave. AM and FM are two different methods.
The wave HEIGHT changes to encode the signal
The wave SPEED changes to encode the signal
Simpler, travels farther, but more susceptible to interference (static during storms).
Better sound quality, less interference, but shorter range. That's why FM stations are local!
Radio stations broadcast on specific frequencies. Your radio "tunes" to receive only that frequency while ignoring others.
Your radio's antenna "resonates" at the tuned frequency, picking up that signal strongly.
Each station uses a small range of frequencies. FM stations are spaced 0.2 MHz apart.
Modern radios use digital circuits to precisely filter and amplify the desired frequency.
Right now, thousands of radio signals are passing through your body! Click each device to see its frequency range.
Governments assign frequency bands to prevent interference. It's like assigning lanes on a highway!
WiFi uses unlicensed bands anyone can use. TV stations pay for exclusive licensed frequencies.
You've discovered the invisible world of radio waves - the electromagnetic signals that connect our world wirelessly!
Just like visible light, but with wavelengths too long for our eyes to see.
Higher frequency waves oscillate faster - FM radio uses higher frequencies than AM.
AM radio waves can be hundreds of meters long, WiFi waves are just centimeters!
AM changes the amplitude (height), FM changes the frequency (speed) to encode information.
Different services use different frequency bands to avoid interference.
Put your new knowledge into practice!