1. What does 'binary' mean in computing?
A system that uses only two digits, 0 and 1
Binary uses just two symbols, 0 and 1, instead of the ten digits we use every day.
2. What is a 'bit'?
The smallest unit of data a computer stores, either a 0 or a 1
Everything a computer stores, from photos to games, is ultimately built out of bits.
3. What is a 'byte'?
A group of 8 bits
Bits are grouped into bytes because a single bit on its own can't hold much useful information.
4. Which part of a computer is often called its 'brain', carrying out instructions?
The CPU (central processing unit)
The CPU carries out the instructions that make up every program a computer runs.
5. What does RAM do?
Stores data the computer is actively using, temporarily, while it's switched on
RAM holds what a computer needs right now. It's fast, but it clears when the power goes off.
6. What is a hard drive (or an SSD) mainly used for?
Storing files and data long term, even when the computer is off
Unlike RAM, storage keeps your files even after the computer is switched off.
7. What is an operating system?
The main software that manages a computer's hardware and runs other programs
Windows, macOS and Linux are all operating systems. Every program you open runs on top of one.
8. What is a 'file'?
A named collection of data stored on a computer, like a document or a photo
Documents, photos, songs and programs are all stored as files.
9. What is a 'folder' (or directory) used for?
Organising files into groups
Folders don't hold data themselves. They just group files together so they're easier to find.
10. What is a network, in computing terms?
Two or more devices connected so they can share data
A network can be as small as two connected devices, or as huge as the internet.
11. How does a computer store a letter like 'A'?
As a number, using a code that assigns each character a number
Every character has an agreed number behind the scenes, so computers can store and swap text reliably.
12. A single pixel in a digital image usually stores what kind of information?
Its colour, usually as numbers
An image is really just a grid of tiny coloured dots, each one stored as a number.
13. What does 'hardware' mean?
The physical parts of a computer you can touch
Hardware is the physical machine: screens, chips, cables and casing.
14. What does 'software' mean?
The programs and instructions that tell hardware what to do
Software is the set of instructions running on the hardware, from the operating system down to individual apps.
15. What is an IP address?
A number that identifies a device on a network so data knows where to go
Every device on a network needs an address so data sent to it knows exactly where to arrive.
16. What does DNS mainly do?
Translates human-friendly website names into the IP addresses computers use
Typing a website's name is much easier than remembering its IP address. DNS does that translation for you.
17. What is a server?
A computer that stores information or provides a service to other computers over a network
When you visit a website, your device is talking to a server somewhere that holds the site's data.
18. What is the World Wide Web?
A system of linked pages and information you access through a browser using the internet
The web is built on top of the internet. The internet is the network, the web is the linked pages you browse on it.
19. What does HTML mainly do on a webpage?
Defines the structure and content of a page, like headings, paragraphs and links
HTML is the skeleton of a page: what's a heading, what's a paragraph, what's a link.
20. What does CSS mainly do on a webpage?
Controls how the page looks, like colours, layout and fonts
If HTML is the skeleton, CSS is the styling on top: colours, spacing, fonts and layout.
21. What is an algorithm?
A set of step by step instructions for solving a problem or completing a task
A recipe is an everyday example of an algorithm: a clear sequence of steps to reach a result.
22. What is a 'variable' in programming?
A named place to store a value that a program can use and change
A variable is like a labelled box: the program can look inside it, and can also put a new value in later.
23. Why does a computer use binary (0s and 1s) instead of, say, ten digits like we do?
Its electronic circuits are simplest to build and control with two clear states, like on and off
Two clear states, on and off, are far easier to build reliably into a circuit than ten different levels.
24. An image made up of a grid of tiny coloured squares is usually called what?
A raster or bitmap image, made of pixels
Photos from a camera are typically raster images: a fixed grid of pixels, each storing its own colour.
25. What is the key difference between RAM and long-term storage (a hard drive or SSD)?
RAM is fast but temporary, storage is slower but keeps data when the power is off
RAM is quick to read and write but empties when the computer shuts down. Storage is slower but keeps your files afterwards.
26. What does a 'loop' do in a program?
Repeats a set of instructions, often until a condition is met
Loops let a program repeat work, like checking every item in a list, without writing the same instructions out over and over.
27. What does a 'conditional' (like an if statement) do in a program?
Makes a program follow different instructions depending on whether something is true or false
Conditionals give a program the ability to make a choice, rather than always doing exactly the same thing.
28. Why do computer programs sometimes have 'bugs'?
Human-written instructions can contain mistakes that produce unexpected results
A computer follows its instructions exactly. If those instructions have a mistake, the result is a bug.
29. What is 'debugging'?
The normal process of finding and fixing mistakes in a program
Every programmer debugs constantly. Finding and fixing mistakes is a routine part of writing software, not a sign of failure.
30. Why does visiting a website usually involve both DNS and a server working together?
DNS finds the correct IP address for the website's name, then the browser talks to the server at that address
DNS is like a phone book lookup that happens first, then the browser uses the address it found to contact the actual server.
31. How can a network's DNS filter stop a device reaching a blocked website?
It can refuse to look up the site's IP address, so the browser has nowhere to connect to
Without an IP address to connect to, the browser can't reach the site at all, even though the site itself still exists elsewhere.
32. What is the difference between a file and a folder?
A file holds actual data, a folder just groups files (and other folders) together for organisation
Folders don't store content themselves. They exist purely to organise the files (and other folders) placed inside them.
33. Why do computers group bits into bytes rather than working with single bits at a time?
Grouping into bytes gives a practical unit for storing a full character or a small piece of data
A single bit can only be a 0 or a 1. A byte, with its 8 bits, has enough combinations to represent a full character.
34. What generally happens when a program crashes?
It stops running unexpectedly, usually because it hit an instruction or situation it couldn't handle correctly
A crash is the program giving up when it hits something its instructions didn't account for, not a sign the hardware is broken.
35. Why is a network of just two directly connected computers still called a network?
A network simply means devices connected together to share data, regardless of how many
The word network just describes the connection itself: any set of devices able to share data with each other.
36. Why does a computer need an operating system instead of running programs directly on the hardware?
The operating system manages shared resources like memory and storage so multiple programs can run without conflicting
Without something coordinating access to memory, storage and the screen, programs would constantly interfere with each other.
37. Why is an IP address alone not usually enough to reliably reach a particular website over time?
A website's IP address can change, which is why DNS is used to look it up by name instead of remembering a number
Names are stable even when the underlying address changes, which is exactly the problem DNS solves.
38. What is the practical difference between an algorithm and the code that implements it?
An algorithm is the idea or the steps, while code is that idea written in a specific programming language a computer can run
You could describe the same algorithm in plain English, then write it as code in several different programming languages.
39. Why might the exact same algorithm run faster on one computer than another?
Differences in hardware, like CPU speed and available memory, affect how quickly instructions are carried out
The instructions might be identical, but the hardware carrying them out can still make a real difference to speed.
40. What does it mean for a loop to be 'infinite' by mistake?
Its condition to stop is never met, so it keeps repeating and the program never moves on
A loop needs a way to know when to stop. Miss that, and the program can get stuck repeating forever.
41. Why is testing a program with unusual or unexpected inputs a normal part of programming?
Bugs often show up only in situations the programmer didn't originally think to check
The situations nobody thought to test are exactly where bugs tend to hide.
42. Why can a large digital photo take up much more storage space than a small one?
A larger photo usually has more pixels, and each pixel needs its own stored colour information
More pixels means more individual pieces of colour information to store, which adds up to a bigger file.
43. What is the main job of a web browser?
To request pages from servers, then interpret HTML and CSS to display them to you
A browser is a translator: it fetches a page's HTML and CSS and turns that into what you actually see on screen.
44. Why might a device on a home network be given a different IP address each time it connects?
Many networks assign addresses automatically from a shared pool, rather than giving every device a permanent one
Automatically handing out addresses from a shared pool is simpler to manage than giving every device a fixed one forever.
45. At a basic level, what is a large language model (the kind of AI behind many chatbots) actually doing when it answers a question?
Predicting the most likely next words, based on patterns learned from huge amounts of text
It's generating text one likely piece at a time based on patterns, which is very different from looking a fact up.
46. Why do large language models sometimes state confidently wrong information?
They generate text based on patterns in their training data, and don't check facts against the real world before answering
Confident-sounding text and correct text are not the same thing. A model generates what sounds likely, not what it has verified is true.
47. Why is binary a natural fit for how transistors, the tiny switches inside a computer chip, actually work?
A transistor is easiest to build and control with just two clear states, like on and off, which maps directly to 0 and 1
A transistor's simplest reliable behaviour is being either on or off, which lines up perfectly with binary's two digits.
48. Compression can make an image file much smaller. What is a general idea behind how this works?
It finds patterns or repeated information in the data and stores it more efficiently rather than storing every pixel separately
Rather than storing every single pixel from scratch, compression looks for patterns and shortcuts so the same picture takes less space.
49. Why might two websites with completely different addresses (URLs) actually be running on the same physical server?
A single server can host many separate websites at once, each identified by its own domain name
One powerful server can quietly host dozens or hundreds of different sites, each reached through its own separate name.
50. Why is 'the computer made a mistake' often not quite accurate when software behaves unexpectedly?
Computers follow instructions exactly, so unexpected behaviour usually traces back to a mistake in the instructions a person wrote
A computer does exactly what it's told. When something goes wrong, the instructions themselves are almost always where the mistake lives.