A kid on a couch aims a remote in a straight line at a TV while a phone sends teal and blue radio rings spreading out to a router on a shelf.

Why aim a remote, but not your phone?

A remote only works if you aim it at the TV. But your phone talks to the router in the next room without pointing at anything. Same invisible signals — so why the different rules?

They are not all the same thing. Some signals are light — they shoot out in one straight beam. Some are radio — lazy waves that spread out in every direction.

A split diagram: on the left a straight red-orange light beam shoots one direction, on the right teal and blue radio rings spread outward in every direction.

Infrared — the TV remote's signal — is really light. Tap it: light shoots out in ONE straight line. That's why you must aim a remote, just like a flashlight.

tap to send the light →

WiFi and Bluetooth are radio. Tap it: radio spreads out EVERY direction at once, like ripples in a pond. Nothing to aim — it reaches gadgets all around.

tap to send the radio →

Your turn. Tap SEND and watch all three race out to the gadgets. WiFi shouts across the house; Bluetooth only whispers, so it stays close.

Now close a door.

A kid and a sender on the left of a tall solid brick wall, with a red beam and teal and blue rings still approaching the wall and the far side hidden.

A solid wall drops between you and the gadgets. Some signals are light, some are radio. When the door shuts all the way — what happens to each one? 🤔

You saw: infrared is light, WiFi & Bluetooth are radio.

Close the door all the way — which signals still reach the gadgets?