Topic
Computers & signals
Screens, data, code, and messages that travel — 28 tiny stories from every shelf.
Bouncing all the way
How Does Light Go Round a Bend?
Light travels round bends in a fibre by reflecting off the inside walls thousands of times a metre.
Let’s go →Same family, different size
Is Radio Really a Kind of Light?
Radio is genuinely light, just with waves metres long instead of fractions of a millimetre.
Let’s go →A recipe with no judgement
What Makes Something an Algorithm?
An algorithm is a sequence of steps precise enough that a machine can follow it without judgement.
Let’s go →On and off is enough
How Do Computers Count With Only Two Digits?
Computers count in binary because a switch has just two states, and place value does the rest.
Let’s go →Order makes finding easy
Why Do We Sort Things?
Sorting things into order makes finding any one of them far faster.
Let’s go →Physics run forward
How Can Anyone Predict Tomorrow?
A forecast measures today's air everywhere and calculates it forward using known physics.
Let’s go →Predicting, not just reacting
What Does Your Brain Do?
The brain constantly predicts what is happening and corrects itself using the senses.
Let’s go →Light in, picture built
How Do Your Eyes See?
Eyes convert light into nerve signals, and the brain builds the image.
Let’s go →Wide, narrow, wide
How Does a Shop Scanner Read a Barcode?
A barcode is a number written as stripes, and the scanner reads it by measuring reflected light as it sweeps across.
Let’s go →Counting light in tiny buckets
How Does a Photo Get Caught?
A photo is a count of light: a lens focuses it, a shutter times it, and a grid of wells measures it.
Let’s go →Someone else's computer, in a shed
Where Is the Cloud?
The cloud is racks of computers in big buildings, holding your files and sending them over the internet when you ask.
Let’s go →A desk and a filing cabinet
Where Does a Computer Keep Things?
A computer uses fast memory that empties when the power goes, and slower storage that keeps things permanently.
Let’s go →Instructions, and nothing but
What Is a Computer Program?
A program is a list of exact instructions a computer follows in order, with tests and repeats to change the path.
Let’s go →A relay, not a delivery
How Does an Email Find You?
An email is passed between servers, sorted by the part after the @, and waits on a server until your device collects 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 and works out the only place it could be.
Let’s go →Adding a wave to its own mirror
Why Does Noise-Cancelling Work?
Noise-cancelling works by recording the noise, playing its mirror image, and letting the two waves add up to almost nothing.
Let’s go →Millions of tiny corrections
How Does a Computer Learn?
A computer learns by guessing, being told how wrong it was, and nudging its own numbers — millions of times over.
Let’s go →Somebody else's computer
Where Does a Website Actually Live?
A website lives as files on a real computer, and reaches you as small addressed packets passed router to router.
Let’s go →Guessing is done by machine
Why Do Passwords Have to Be Long?
Passwords must be long because computers guess billions per second, and each extra character multiplies the work.
Let’s go →Dots, fired one at a time
How Does a Printer Place Ink So Exactly?
A printer breaks a page into a grid of dots and fires a tiny drop of ink at each one as the head sweeps across.
Let’s go →A wobble carried on a wave
How Does Music Get Into a Radio?
A radio station rides sound on a steady wave by wobbling it, and your radio picks out one wave and reads the wobble back.
Let’s go →A light you cannot see
How Does a Remote Control Reach the Television?
A remote control blinks an invisible infrared light in a pattern, and the television has a sensor that reads it.
Let’s go →Sense, decide, move
What Makes Something a Robot?
A robot senses the world, decides what to do about it, and moves — and it is the deciding that makes it a robot.
Let’s go →Millions of tiny lights
Why Are Pictures Made of Dots?
Screens show pictures as a grid of dots mixing red, green and blue, redrawn fast enough to look like motion.
Let’s go →Three colours, several million times
How Does a Television Make a Picture?
A television makes pictures out of millions of tiny red, green and blue lights, each given a brightness many times a second.
Let’s go →It notices charge, not pressure
How Does Glass Feel Your Finger?
A touchscreen does not feel pressure; it notices your body stealing a little charge from a grid of invisible wires.
Let’s go →Redrawn sixty times a second
How Does a Video Game Work?
A game reads your controls, works out the new state of its world, and draws a fresh picture — sixty times a second.
Let’s go →Radio you cannot hear
How Does the Internet Cross a Room?
Wifi is radio: data rides on a wave that is wobbled in a pattern your phone knows how to read back.
Let’s go →