Internet, WWW & Web Browsers
The internet is the road, the world wide web is the shops along it, and the browser is the vehicle that takes you there. Learn how a URL becomes an IP address, how HTTP delivers your page, why HTTPS keeps your data safe, what a browser actually does — and how session and persistent cookies fit in.
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What do I need to know before I start?
This page is about how the internet delivers a web page to you. Three ideas sit at the centre. First, the internet is the global infrastructure — a worldwide network (WAN) of cables and connected devices — while the world wide web is the content: the pages and sites carried over it. Second, every site has a text URL and every device a numeric IP address, and a DNS converts one to the other. Third, a web browser — whose main purpose is to render HTML and display web pages — uses HTTP/HTTPS to request a page from a web server and render it, storing cookies along the way. The marks come from exact wording, not the general idea.
By the end of 5.1–5.3 you can…
| You can… | Why it matters |
|---|---|
| Define the internet and the WWW, and say why they differ | A frequently tested distinction — the two are often confused |
| Break a URL into protocol, domain name and web page/file | Answers "identify the parts" questions and names the domain correctly |
| Describe how DNS, IP addresses and HTTP retrieve and display a page | Process questions reward the right order and the right terms |
| Compare HTTP and HTTPS, including the certificate handshake | Questions can ask for the extra steps HTTPS adds |
| State browser functions beyond the address bar and cookies | Asked directly in Feb/Mar 2026 — you need three ready |
| Distinguish session and persistent cookies with different examples | Two marks, and the examples must not repeat |
Cambridge-approved terms
The global network (WAN) — the infrastructure of cables and connected devices spanning the world.
The collection of all web pages and websites made available; accessed by using the internet.
Text address of a page: protocol + domain name + web page/file name.
A unique address that identifies a device on a network or the internet.
A server holding a database of domain names and matching IP addresses; translates a URL/domain into an IP address.
The computer that stores the web pages of a site and sends them when requested.
Hypertext Transfer Protocol — the rules for transmitting web pages.
Secure HTTP — a digital certificate authenticates the site and the data is encrypted using SSL/TLS.
A small text file sent by a website and stored by the browser on the user's computer, holding data about the user or their browsing.
The tables you must know cold
The three parts of a URL
| Part | Example | What it is |
|---|---|---|
| Protocol | https:// | The rules for transmitting the data (HTTP, or HTTPS if secure) |
| Domain name | www.cambridge.org | The unique name of the web server that stores the site |
| Web page / file | /education | The specific page or file requested; omit it and the home page is returned |
HTTP vs HTTPS
| Feature | HTTP | HTTPS |
|---|---|---|
| Encryption | None — plain text | Encrypted using SSL/TLS |
| Digital certificate | Not required | Required — from a certificate authority |
| Use for | Basic content (rare now) | Logins, payments, personal data |
Requesting a page — the order
| Step | What happens |
|---|---|
| 1 | Browser sends the URL/domain name to a DNS |
| 2 | DNS finds the matching IP address (passes to a higher DNS if not found) |
| 3 | DNS returns the IP address to the browser |
| 4 | Browser sends an HTTP request to the web server at that IP |
| 5 | Server returns HTML/CSS/script; the browser renders the page |
Traps that regularly cost marks
Check yourself — tap to reveal
Say the answer out loud in exam wording, then tap to check.
✅ Ready for Learn?
You've met the terms and the traps. Open the Learn tab for the URL breakdown, the step-through retrieval diagram and the cookie examples in action — then test yourself in Activities and Practice.
📚 From the Textbook
"The internet and the world wide web — aren't they the same thing?" Bonus points if you already know they aren't. The internet is an infrastructure: all the components and cables that connect one device to another. It's one huge network — specifically a wide area network (WAN) spanning the entire world. The world wide web is the collection of all the websites and web pages that have been made available. You use the internet to access the WWW — in the same way you use a road to reach a shop. The road isn't the shop; the internet isn't the WWW. Every website has a text-based address called a URL, and every device on the internet has a numeric address called an IP address. Getting from one to the other is the job of the DNS — step through it below.
💡 Getting Started
Think about what you already know about keeping yourself safe on the internet (e-safety). Create a poster for a younger audience that tells them how to use the internet safely and what to do if they find something that upsets them.
🔬 Computer Science in Context: Tim Berners-Lee
The world wide web was invented by Tim Berners-Lee in 1989 at CERN. He had lots of computers, each with different information stored on them, and he was fed up of logging into each one separately. Networks already existed, so he combined them with an emerging technology called hypertext. By October 1990 he had built the three fundamental parts of the WWW: HTML (the language for writing pages), URL (the address system), and HTTP (the protocol for sending pages). By the end of 1990 the first web server was running and the first web page — describing the WWW project itself — was live.
💬 Discussion — what if the DNS stopped working?
People remember names like www.bbc.co.uk, but data is sent to IP addresses. The DNS bridges the gap: it looks the domain name up in its database and returns the matching IP address. If it doesn't have the entry, it passes the request to another DNS higher up. Imagine the DNS your device uses stopped working, while the cables, routers and web servers were all still fine. Could you still reach your favourite websites by typing their URLs? What could you type instead, and why would hardly anyone do that?
⚠️ The Cambridge Exam Trap — Internet vs World Wide Web
This is one of the most common mix-ups in this topic. Candidates often use the two terms as if they mean the same thing. They don't.
The INFRASTRUCTURE. A global network (WAN) of cables, servers and connected devices.
Think of it as the road system. It exists physically. It carries traffic.
The CONTENT. All the websites and web pages that have been made available.
Think of it as the shops on the road. It's what you visit — accessed using the internet.
URL Anatomy — click each part
Every URL has three parts. Click each block to see what it does.
:// that follows the protocol is punctuation the browser expects; you don't say it in an exam.www is a sub-domain, cambridge is the site name, .org is the top-level domain./education tells the server which page to send back.Requesting & retrieving a web page — step through it
Use the buttons to walk through what actually happens between you typing a URL and seeing the page.
HTTP vs HTTPS
| Feature | HTTP | HTTPS |
|---|---|---|
| What it is | Hypertext Transfer Protocol | Hypertext Transfer Protocol Secure |
| Encryption | No — data sent in plain text | Yes — data encrypted using SSL/TLS |
| Digital certificate | Not required | Required — issued by a certificate authority |
| When to use | Basic content (rare now) | Anything sensitive: logins, payment, personal data |
- Before requesting the page, the browser asks the web server for its digital certificate.
- The web server sends a copy of the digital certificate back.
- The browser checks the certificate is authentic (issued by a trusted certificate authority).
- If authentic → communication continues, data is encrypted using SSL/TLS.
- If not authentic → the browser warns the user the site is not secure.
What does a web browser actually do?
The Feb/March 2026 paper asked for three functions of a web browser beyond providing an address bar and storing cookies. Here's the list — learn six so you always have three ready.
Renders the HTML, applies the CSS and runs any active script (e.g. JavaScript) to display the page.
Saves the URLs of pages the user wants to return to.
Keeps a list of pages the user has visited.
Lets the user open several pages at once in the same window.
Back, forward, refresh, address bar and stop.
The page automatically loaded when the browser opens. Useful extra — not on the syllabus list.
Cookies — session vs persistent
A cookie is a small text file sent by a website and stored by the web browser on the user's computer, holding data about the user or their browsing activities. Two kinds — you must be able to give one example of each.
🍪 Session cookie
Deleted when the browser is closed. Only lasts for the current browsing session.
🍪 Persistent cookie
Saved on the device. Stays there across sessions, until it expires or the user deletes it.
⭐ Activity 1 — Feature Identifier
Read the description. Name the concept.
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🎮 Activity 2 — Internet vs WWW Sorter
The classic mix-up. Is this a description of the Internet or the World Wide Web?
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🎮 Activity 3 — Cookie Sorter
Session or persistent? Read the use case and pick.
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🎮 Activity 4 — Retrieval Order
The five steps below are out of order. Click them in the correct order (1 → 5). Get it wrong and you'll be told which step you missed.
⏱️ Activity 5 — 60-Second Web Sprint
Rapid recall. Match each description to the correct term.
Practice questions
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Cambridge-style questions from m26 & past papers
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Review quiz
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Exam traps
Memory triggers
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Skills breakdown
Next up
Internet, WWW and browsers sorted. Next is 5.4 Digital Currency & Blockchain Lab — what a digital currency is, and how a blockchain ledger tracks every transaction.