Tag
Computers & signals
Screens, data, code, and messages that travel — 33 tiny stories across 5 shelves.
How things work
Everyday machines, taken apart — 23 stories.
All how things work →And that is the boring half
Your Phone Beats the Computer That Flew to the Moon
The computer that landed Apollo 11 had less memory than one photo, and it was enough — because it did one job perfectly rather than everything adequately.
Let’s go →Wide, narrow, wide
How Does a Shop Scanner Read a Barcode?
Guard bars differ at each end, so a label scanned backwards still reads. The stripes carry no price at all — that lives in the shop's own computer.
Let’s go →Counting light in tiny buckets
How Does a Photo Get Caught?
A photo is a count of light: the lens focuses it, the shutter times it, and a grid of tiny wells measures how much landed in each one.
Let’s go →Someone else's computer, in a shed
Where Is the Cloud?
The cloud is not in the sky. It is racks of computers in big cooled buildings, holding copies of your files and a vast electricity bill.
Let’s go →A desk and a filing cabinet
Where Does a Computer Keep Things?
A computer has two places to put things, and the difference is what happens at power-off: fast memory empties, slower storage does not.
Let’s go →Instructions, and nothing but
What Is a Computer Program?
A program is exact instructions run in order, with tests and repeats to change the path, followed by something that understands none of it.
Let’s go →A relay, not a delivery
How Does an Email Find You?
An email is not carried to you. It is handed from server to server using the part after the @, and waits until your device asks for it.
Let’s go →Four clocks and some arithmetic
How Does a Phone Know Where It Is?
Nothing tracks your phone. It times signals from several satellites, turns each delay into a distance, and solves for the only point that fits.
Let’s go →Adding a wave to its own mirror
Why Does Noise-Cancelling Work?
A predictable engine drone can be anticipated and cancelled, but clattering cutlery is different every time and mostly gets through regardless.
Let’s go →Millions of tiny corrections
How Does a Computer Learn?
Nobody writes the rules for recognising a cat. The computer guesses, is told how wrong it was, and nudges its own numbers a million times.
Let’s go →Somebody else's computer
Where Does a Website Actually Live?
A website is not in the air. It is files on a real machine somewhere, reaching you as small addressed packets handed from router to router.
Let’s go →Rows and columns, checked constantly
How Does a Keyboard Know Which Key You Pressed?
No wire runs from every key. They are wired as a grid and scanned hundreds of times a second, so twenty wires find one key among a hundred.
Let’s go →Guessing is done by machine
Why Do Passwords Have to Be Long?
Nobody sits typing guesses. A computer tries billions a second and every human trick first, so length beats cleverness every single time.
Let’s go →Dots, fired one at a time
How Does a Printer Place Ink So Exactly?
A resistor boils a speck of ink for a few millionths of a second and the steam bubble shoves one drop out. Black is added because three inks make mud.
Let’s go →A wobble carried on a wave
How Does Music Get Into a Radio?
A station sends out one steady wave and wobbles it in time with the sound; your radio picks that wave alone and reads the wobble back off.
Let’s go →A light you cannot see
How Does a Remote Control Reach the Television?
Infrared will not pass through a sofa but bounces nicely off a pale ceiling, which is why aiming a remote at the wall so often works anyway.
Let’s go →Sense, decide, move
What Makes Something a Robot?
A washing machine follows instructions; a robot senses what is actually happening and decides what to do about it, many times a second.
Let’s go →Millions of tiny lights
Why Are Pictures Made of Dots?
Nothing on a screen ever travels anywhere. Red and green side by side read as yellow, and your eye cannot separate them, so it reports the mixture.
Let’s go →Mostly by not being sent
How Does a Picture Get to Your Television?
A moving picture is far too much to send, so almost all of it is thrown away: only what changed, and only what your eye would notice, makes the trip.
Let’s go →It notices charge, not pressure
How Does Glass Feel Your Finger?
A touchscreen never notices pressure. It measures charge draining into the salty water you are made of, at every crossing of a wire grid.
Let’s go →Not through the sky
The Internet Runs Along the Sea Floor
About 99 per cent of international internet traffic crosses the ocean floor by fibre-optic cable rather than satellite — and ships have laid it since 1858.
Let’s go →Redrawn sixty times a second
How Does a Video Game Work?
A game is not a moving picture. It reads your controls, recalculates its whole world and draws a fresh still image sixty times a second.
Let’s go →Radio you cannot hear
How Does the Internet Cross a Room?
Wifi is radio. Your data rides on a wave wobbled in a pattern both ends agreed to read, and every device sharing that channel waits its turn.
Let’s go →Math
Number ideas with toys — 5 stories.
All math →A recipe with no judgement
What Makes Something an Algorithm?
An algorithm is a list of steps precise enough to need no judgement: every decision definite, every step doable, and the whole thing finishes.
Let’s go →On and off is enough
How Do Computers Count With Only Two Digits?
A switch is only ever off or on, so computers count with two digits. Place value that doubles each column can still write any number you like.
Let’s go →Proved in 1976, by machine
Four Colours Are Always Enough
Four colours suffice for every possible map — a claim that resisted proof for over a century, then fell to a computer checking 1,936 cases no human could.
Let’s go →The catalogue is not the shelf
How Does a Library Find One Book?
Shelves cannot be sorted by subject and by author at once, so a library keeps a small separate list of pointers that sends you to one exact spot.
Let’s go →Order makes finding easy
Why Do We Sort Things?
Unsorted, finding one thing among a thousand costs 500 checks on average. Sorted, halving the problem at every look gets you there in ten.
Let’s go →Physics
Invisible forces you can play with — 2 stories.
All physics →Bouncing all the way
How Does Light Go Round a Bend?
Light strikes the inside wall of a glass fibre so shallowly that it reflects perfectly, thousands of times a metre, tracing the cable round bends.
Let’s go →Same family, different size
Is Radio Really a Kind of Light?
Radio is genuinely light, just stretched to waves metres long instead of fractions of a millimetre. That length is why it passes through walls.
Let’s go →Life & body
Seeds, hearts, senses, and growing things — 2 stories.
All life & body →Predicting, not just reacting
What Does Your Brain Do?
Your brain runs a constant prediction of what is happening and uses the senses to correct it. That is exactly why an illusion can fool you so completely.
Let’s go →Light in, picture built
How Do Your Eyes See?
Eyes turn light into nerve signals. The picture you see is assembled afterwards by the brain — patched, corrected, and rather less direct than it feels.
Let’s go →Earth & sky
Weather, light, and the air around us — 1 story.
All earth & sky →