The magic you already live with
You have a router in your home. You connect to WiFi at coffee shops, at airports, at your friend's place. If it went down for a day, you'd lose your mind. WiFi is one of the most essential technologies in your daily life.
Can you explain how it works?
Not vaguely. Not "it sends signals." Actually explain what's happening — what kind of signals, how they carry information, how your phone knows the data is meant for it and not your roommate's laptop.
Most people can't. And that's fine — we've always lived alongside technology we don't fully understand. But here's where it gets interesting: we're about to live with a lot more of it. When superintelligent AI starts producing novel materials, new physics applications, and systems with no human-readable explanation for how they work, our relationship with technology will change. Or rather — it won't change. We already depend on things we can't explain. We've been practicing for decades.
By the end of this article, you'll actually understand one of them.
Everything starts with a ripple
Drop a rock in a pond. Ripples spread out in every direction. That's a wave — energy moving through space.
Sound works the same way. When you talk, your vocal cords vibrate air molecules. Those vibrations travel outward, hit your friend's eardrum, and their brain turns the vibrations back into words. The sound didn't teleport — it rippled.
Here's the one concept you need: frequency — how many ripples happen per second. A high-pitched whistle has a higher frequency than a low drum. Both are sound waves. Same type of energy, different rhythm.
That's the only physics you need. Everything else builds on it.
There are waves you can't see
Light is a wave. But the light your eyes detect — red, blue, green — is a tiny sliver of a much larger spectrum.
Below visible light in frequency, you get infrared (the warmth you feel from a fire), then microwaves, then radio waves. Above visible light, you get ultraviolet (sunburns), X-rays (broken bones), and gamma rays (nuclear reactions).
All of these are the same fundamental thing: electromagnetic waves. Same physics, different frequency. The only thing that changes is how fast the wave oscillates.
WiFi lives in the microwave range — 2.4 billion or 5 billion oscillations per second. It's literally the same kind of energy as visible light, just at a frequency your eyes can't detect.
Your router is a flashlight you can't see. Right now, it's spraying invisible light in every direction inside your home. Your walls are partially transparent to it. Your phone is picking it up and reading it.
That's not a metaphor. That's what's physically happening.
See it for yourself
The simulation below is a top-down floor plan of a small apartment with a WiFi router in the living room. The expanding rings are the electromagnetic waves radiating outward — invisible light, pulsing at billions of cycles per second. The drywall and concrete walls between rooms absorb and weaken the signal as it passes through.
Drag the router around. Move the devices between rooms and watch the signal strength change. The modulation visualizer at the bottom shows what the wave actually looks like when it's carrying data.
Blinking a flashlight really fast
So the router is blasting invisible light in all directions. But how does that light carry a webpage? A video? A song?
Imagine you and a friend are on opposite hilltops with flashlights. You agree on a code: a bright flash means 1, a dim flash means 0. Now you can send numbers — one flash at a time.
WiFi does exactly this, but instead of bright and dim flashes, it changes the shape of the wave. It might make the wave taller or shorter (amplitude modulation), speed up or slow down the oscillations (frequency modulation), or shift the wave's timing (phase modulation). Each variation encodes a 0 or a 1.
This is called modulation — encoding information by subtly changing a wave's properties. Your router does this billions of times per second. The changes are so fast and so small that the wave still looks like a smooth signal — but hidden inside those tiny variations is your entire Netflix stream.
If you scroll back up to the simulation, the modulation visualizer at the bottom shows exactly this: the wave changes its amplitude to carry the binary message "Hi" — 01001000 01101001. Big wave = 1, small wave = 0.
Everything is just numbers
Here's the part that makes the whole system click: everything digital is just numbers.
That photo of your dog? It's a grid of pixels. Each pixel is a color. Each color is a number. A 12-megapixel photo is roughly 36 million numbers, stored as 0s and 1s.
That song you're streaming? A sequence of numbers representing air pressure at 44,100 points per second.
This article you're reading right now? A sequence of numbers, where each number maps to a letter, space, or punctuation mark.
All of it — every photo, every video, every message, every webpage — is a long sequence of 0s and 1s. And if you can send 0s and 1s on a wave (which we just established), you can send literally anything.
That's the whole trick. There is no special "internet substance" that flows through the air. There are just invisible light waves, modulated to carry numbers, and those numbers reassemble into everything you see on a screen.
How does your phone know it's for you?
Your router might be serving five devices at once — your laptop, your phone, your smart TV, your roommate's tablet, your partner's phone. They're all bathed in the same invisible light. How does each device get the right data?
Every device that connects to a network has a unique address — called a MAC address (Media Access Control — nothing to do with Apple). It's like a mailing address stamped on the device's WiFi hardware at the factory.
When your phone asks the router for a webpage, it includes its address in the request. The router remembers who asked for what. When the data comes back from the internet, the router wraps it in a packet labeled with your phone's address and broadcasts it. Your phone recognizes its own address and grabs the packet. Every other device ignores it.
That's why your roommate's Netflix doesn't show up on your phone. The router is a mail carrier, sorting deliveries by address.
Why the password?
Here's the catch: your router is broadcasting invisible light in every direction. Your walls are partially transparent to it. Which means your neighbor's phone can pick up those waves too.
Without encryption, anyone within range could read the wave shapes and decode them back into your data — your passwords, your messages, your browsing history. All of it, floating through the air in plaintext.
When you type a WiFi password for the first time, your device and the router perform a mathematical handshake — they agree on a shared secret scrambling method. From that point on, every packet of data is scrambled before it's sent and unscrambled on the other end.
Your neighbor can still detect the waves — the invisible light doesn't stop at your walls — but the data is garbled without the key. It's like overhearing a conversation in a language you don't speak.
This is what WPA2 and WPA3 (WiFi Protected Access) do. The password isn't transmitted over the air. It's used to derive the encryption key locally on both your device and the router. Even if someone captures every wave your router emits, they can't reconstruct the original data without the key.
Why does it suck sometimes?
Now you know enough to understand why WiFi has bad days.
Walls absorb the signal. The wave loses energy every time it passes through solid material. Drywall takes a moderate toll. Concrete is devastating. Metal is nearly opaque. In the simulation above, drag the phone in the bathroom — it's behind both a drywall and a concrete wall, and the signal suffers for it.
Distance weakens the signal. Electromagnetic waves spread out as they travel, just like ripples in a pond get shorter as they expand. The further your device is from the router, the weaker the signal it receives. The energy doesn't disappear — it's just spread across a larger area, so your device's tiny antenna catches less of it.
Interference from other devices. Your neighbor's router, your microwave oven, your Bluetooth headphones — they all operate in similar frequency ranges. When too many devices are broadcasting on the same frequency, they overlap and garble each other. It's like trying to have a conversation at a loud party — the more people yelling in the same room, the harder it is to hear anyone clearly.
2.4 GHz vs 5 GHz: the range-speed trade-off. Lower frequency waves (2.4 GHz) travel farther and pass through walls better, but carry less data per second — about 50–100 Mbps in practice. Higher frequency waves (5 GHz) carry more data — 300+ Mbps — but die faster through obstacles and over distance. Your router's "dual-band" feature lets you pick which trade-off you want. Close to the router with a clear line of sight? Use 5 GHz. Three rooms away through two walls? Use 2.4 GHz.
The comfort of not knowing
You just learned how WiFi works from scratch. Invisible light radiating from a box in your living room, modulated into shapes that carry numbers, routed by address, scrambled with encryption, and decoded by a tiny antenna in your pocket. It's genuinely beautiful engineering. And yesterday, you used it a thousand times without thinking about any of this.
That's the relationship we're about to have with whatever comes next.
Superintelligent AI will produce technologies that no one on Earth fully understands — novel materials designed by optimization processes we can't follow, physics applications discovered by pattern-matching across datasets too large for human minds, systems that work for reasons that can't be decomposed into a tidy explanation.
We'll use them anyway. We'll grow accustomed to them. We'll lose our minds when they go down for ten minutes.
The question isn't whether we'll understand the next wave of technology. It's whether that bothers us — because it probably should, at least a little.