Wirebook › Glossary › Radio wave
What is a radio wave?
In one sentence: An invisible wave of energy that travels at the speed of light. Wi-Fi, mobile phones and FM radio all use them.
A little more
Radio waves are the same kind of energy as light, just with much longer waves that our eyes can't see. They travel at the speed of light and can pass through many materials, getting weaker as they go.
How fast a wave wiggles is its frequency. Wi-Fi uses 2.4 billion (2.4 GHz) or 5 billion (5 GHz) wiggles a second. Lower frequencies travel through walls better; higher ones carry more data but fade sooner.
It's a bit like… Ripples spreading on a pond: they get smaller the further they go, and big rocks leave a calm shadow behind them.
See it in action
- 7Why does Wi-Fi get weaker through walls?Build a little house, drag the router around and watch the Wi-Fi signal spread room by room.7 min · interactive
- 9How does a map know where you are?Find a hidden phone using nothing but satellite clocks: listen to each satellite, draw its ring and watch the rings meet.7 min · interactive
- BonusHow does a photo fly to the phone next to you?Send a pretend photo to the phone next to you and watch how AirDrop and Quick Share really work: a tiny Bluetooth shout to find each other, a private Wi-Fi lane with no router, and numbered pieces that fly over like paper aeroplanes and click back together like a jigsaw.8 min · interactive