Blog topic
Technology articles
How the internet, DNS, encryption, WiFi and QR codes work, what an algorithm, a database, a CPU, a GPU, RAM and cache memory are, and plain-language guides to machine learning, cloud computing and cybersecurity. Written for someone who uses these things every day and has never been told what is underneath.
33 explainers, newest first. Each one ends with real questions from the unit that teaches it, so you can read the explanation and then check whether it stuck.
These are the readable companion to the Technology track, which holds 18 units and 2,147 practice questions. If you are starting the subject rather than looking something up, the study guide is the better place to begin.
How Do Canal Locks Work? Lifting a Boat With Nothing but Water
A lock raises or lowers a boat between two water levels by filling or emptying a chamber. How the gates and paddles work, and how Panama lifts a ship 26 metres.
October 23, 20268 min readHow Do Bridges Stay Up? Beams, Arches, Suspension and the Forces Between
Every bridge carries its load to the ground by one of a few strategies, and the strategy sets its shape and span. How beams bend, arches push and cables pull.
October 18, 20268 min readHow Are Tunnels Dug? Boring Machines, Blasting and the Channel Tunnel
A tunnel is dug by cutting rock or soil at the face and holding up the ground behind, by machine, explosive or shield. How each works, and the Channel Tunnel.
October 15, 20268 min readWhat Is Open Source Software? Code Anyone Can Read, Change and Share
Open source software is published with its source code and a licence letting anyone use, alter and pass it on.
October 13, 20268 min readHow Does Radar Work? Radio Echoes That See Through Cloud and Dark
Radar sends out pulses of radio waves and times the echoes to find where things are. How range, direction and speed are measured, and how it was invented.
October 11, 20268 min readHow Does Bluetooth Work? Short-Range Radio That Hops Between Channels
Bluetooth links headphones, cars and watches over a few metres of radio. How devices pair, why the signal hops 1,600 times a second, and why the name is Viking.
October 9, 20267 min readHow Does a Transistor Work? The Switch That Built the Modern World
A transistor is a switch with no moving parts, turned on and off by a voltage. How a slice of silicon controls current, and why that lets it compute.
October 7, 20268 min readHow Does a Touchscreen Work? Why Glass Can Feel a Finger
A phone screen senses a fingertip's tiny electrical effect on a grid of invisible electrodes. How capacitive touch works and why gloves defeat it.
October 5, 20267 min readHow Does a Lithium-Ion Battery Work? Charging, Discharging and Wearing Out
A phone battery shuttles lithium ions between two layered materials. What happens on charge and discharge, why capacity fades, and why cells burn.
October 2, 20267 min readHow Do Computers Store Images? Pixels, Bytes and Compression
A photo is a grid of numbers, three per dot. Why a phone picture would be 36 megabytes without compression, how JPEG throws detail away.
September 30, 20269 min readHow GPS Works: Satellites, Clocks and a Little Relativity
A phone finds itself by timing signals from satellites 20,000 kilometres up. Why it needs four, why the clocks allow for Einstein, and what limits accuracy.
September 9, 20267 min readWhat Is an IP Address? How Devices Find Each Other Online
Learn how Internet Protocol addresses identify network locations, how IPv4 and IPv6 differ, and why public and private addresses matter.
August 17, 202610 min readWhat Is a Firewall? How Network Traffic Gets Filtered
Learn how firewalls inspect and filter network traffic, use security rules, and help protect devices and networks from unwanted connections.
August 17, 20268 min readWhat Is Two-Factor Authentication? Why a Second Check Improves Security
Learn how a second kind of proof can protect an account even when a password is stolen, guessed, or reused.
August 17, 20269 min readHow Do Search Engines Work? Crawling, Indexing, and Ranking Explained
Learn how crawlers discover pages, indexes organise information, and ranking systems choose useful results for a query.
August 17, 20269 min readWhat Is a VPN? How a Virtual Private Network Protects Traffic
Learn what a VPN is, how a virtual private network creates an encrypted tunnel, what it can protect, and what it cannot hide about your online activity.
August 17, 20268 min readWhat Is Cache Memory? How Fast Storage Helps a CPU
Learn what cache memory is, why CPUs keep frequently needed data close by, how cache levels work, and why cache is faster but smaller than main memory.
August 17, 20269 min readWhat Is Machine Learning? A Beginner-Friendly Explanation
Learn how computers find patterns from data, how training differs from testing, and why model quality depends on examples.
August 14, 20269 min readHow Do QR Codes Work? A Simple Technology Guide
Learn how the black and white pattern stores data, helps cameras find orientation, and uses error correction to survive damage.
August 14, 20268 min readWhat Is Cloud Computing? A Beginner-Friendly Technology Guide
Learn how remote servers provide storage, software, and computing power, plus the main benefits, limits, and common service models.
August 14, 20269 min readHow Does Encryption Work? A Beginner-Friendly Guide
Learn how plaintext becomes ciphertext, why keys matter, and how symmetric and public-key encryption protect data.
August 14, 202610 min readWhat Is a Database? How Organised Data Can Be Stored and Queried
Learn how structured data, tables, records, keys, and queries help software store, find, connect, and update information.
August 14, 20269 min readWhat Is an API? How Software Programs Communicate
Learn how application programming interfaces let software request data or actions through defined rules, endpoints, and responses.
August 14, 202610 min readWhat Is an Operating System? How Your Device Manages Hardware and Apps
Learn how it manages memory, files, hardware, apps, and user input so a computer or phone can work as one system.
August 14, 202610 min readHow Does WiFi Work? From Radio Waves to Internet Data
Learn how devices use radio signals, routers, data packets, and shared wireless channels to connect to a local network and the internet.
August 14, 202610 min readWhat Is RAM? How Computer Memory Helps Apps Run
Learn how random access memory holds active data, why more memory can help multitasking, and how RAM differs from long-term storage.
August 14, 20269 min readWhat Is a CPU? How the Processor Runs Computer Instructions
Learn how the central processing unit fetches, decodes, and executes instructions, and how cores, clock speed, cache, and RAM fit together.
August 14, 20269 min readWhat Is a GPU? How Graphics Processors Handle Parallel Work
Learn how graphics processing units handle many calculations at once, how they differ from CPUs, and why they power more than graphics.
August 14, 20269 min readWhat Is DNS? How Domain Names Find the Right Internet Address
Learn how the Domain Name System translates website names into IP addresses, how lookups work, and why caching makes browsing faster.
August 14, 20269 min readHow Does the Internet Work? A Simple Guide
Learn how does the internet work, from devices and routers to servers, packets, and addresses, with a simple guide to what happens when you go online.
August 13, 20268 min readWhat Is an Algorithm? A Beginner-Friendly Explanation
Learn how step-by-step instructions help computers solve problems, make decisions, sort data, and repeat tasks efficiently.
August 13, 20269 min readHow Does Binary Work? A Beginner's Guide to Bits and Numbers
Learn how computers represent numbers with 0 and 1, how place values work, and why bits can encode much more than numbers.
August 13, 20269 min readWhat Is Cybersecurity? A Simple Guide to Staying Secure
Learn how people and systems protect devices, accounts, networks, and data from attacks, mistakes, and unauthorized access.
August 13, 20268 min read