How Does the Internet Cross a Room?

Step 1 of 5

Wifi spreads out, it does not aim.

A router does not fire a beam at your phone. It fills the room with waves that bounce off walls and floors, arriving from several directions at once.

Step 2 of 5

Data becomes a pattern of wobbles.

Your message is already ones and zeros. The router nudges the radio wave's height and timing to spell out that pattern thousands of times a second.

Step 3 of 5

Both ends agree on the language first.

Before any data moves, your phone and the router introduce themselves, check the password and settle on a speed they can both manage.

Step 4 of 5

Walls and water soak the signal up.

Radio passes through plasterboard easily, brick poorly and water badly. A full fish tank or a thick chimney can matter more than distance does.

Step 5 of 5

Everyone shares the air, so they take turns.

Only one device on a channel may talk at any instant. The rest wait, listen for a gap, and squeeze in — which is why a crowded network feels slow.

Wifi runs at 2.4 and 5 gigahertz, meaning the wave wobbles about 2.4 billion times a second while travelling at the speed of light.