Good Learning Co.
SavannahYear 8
← Computing
ComputingHow computers work20 min★★ difficulty

Networks and the internet

When you open a video, data travels across the world in small pieces in under a second. Here's the journey.

Part of your national curriculum
  • Computer systems and networks: Understand how computer networks, including the internet, can provide multiple services such as the World Wide Web

Lesson overview

What you'll learn in this lesson

Understand how computer networks, including the internet, can provide multiple services such as the World Wide Web

Key learning points

  • • From home to the world
  • • Packets
  • • Internet vs web
  • • Addresses and security

This lesson at a glance

  • 20 minutes
  • 19 parts to scroll through
  • 4 quick checks
  • Marked quiz at the end
  • Gentle pace: short sittings with pauses

Words to know

computernetworksinternetprovidemultiple

Scroll down — the lesson carries on below

Part 1 of 19 · Intro5%
1

Introduction

Part 1 of 19

Networks and the internet illustrationVisual introduction

Picture this

Networks and the internet

When you open a video, data travels across the world in small pieces in under a second. Here's the journey.

In a nutshell

Understand how computer networks, including the internet, can provide multiple services such as the World Wide Web

2

What you already know

Part 2 of 19

Before we start

What you already know

You know computers store data as binary.

Recap: Binary: how computers count
3

Key words

Part 3 of 19

Key words

Words you'll need today

network
Two or more devices connected to share data.
router
A device that directs data between networks, like your home Wi-Fi box.
packet
A small piece of data sent across a network.
IP address
A device's address on the internet, so data reaches the right place.
4

Learning cycle

Part 4 of 19

Learning cycle 1 of 2

Part 1: Networks

A short piece of teaching, then a check to make sure it has landed.

5

Explore the idea

Part 5 of 19

Learn

From home to the world

Your devices join your home network through the router. The router connects to your internet provider, which connects to other networks worldwide, often through cables under the sea.

6

Explore the idea

Part 6 of 19

Learn

Packets

Files are split into packets. Each one carries the destination IP address and its number in the order. They can take different routes and are put back together at the end.

7

Quick check

Part 7 of 19

Quick check

What's a packet?

8

Quick check

Part 8 of 19

Quick check

What directs data between networks?

9

Reset break

Part 9 of 19

Pause

That's sitting 1 of 2 done

Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.

Stop here for now
10

Learning cycle

Part 10 of 19

Learning cycle 2 of 2

Part 2: The internet and the web

A short piece of teaching, then a check to make sure it has landed.

11

Explore the idea

Part 11 of 19

Learn

Internet vs web

The internet is the network of connected networks. The World Wide Web is one service on it, made of web pages. Email, video calls and online games are other services.

12

Explore the idea

Part 12 of 19

Learn

Addresses and security

DNS turns names like bbc.co.uk into IP addresses. The padlock and 'https' mean data is encrypted, so others can't read it on the way.

13

Quick check

Part 13 of 19

Quick check

The World Wide Web is:

14

Quick check

Part 14 of 19

Quick check

What does DNS do?

15

Common mix-ups

Part 15 of 19

Common mix-ups

Things people often get wrong

  • The internet and the web aren't the same. The web runs on the internet.
  • Wi-Fi is just the wireless link to your router, not the internet itself.
16

Challenge round

Part 16 of 19

Game · Sort it

Which of these are true?

Drag each card into the right column. Tap a card first if dragging is fiddly.

True

Not true

17

Challenge round

Part 17 of 19

Game · Fill the gaps

Finish the sentences

Choose the word that belongs in each gap.

The router connects to your internet provider, which connects to other ____ worldwide, often through cables under the sea.

The ____ is the network of connected networks.

18

Mastery quiz

Part 18 of 19

Marked quiz

End of lesson quiz: Networks and the internet

3 questions, marked with the reasoning shown. No timer.

  1. 1. https and a padlock mean data is:

  2. 2. Packets for one file:

  3. 3. Which is an internet service other than the web?

19

Lesson round-up

Part 19 of 19

Lesson round-up

Ready when you are

Quiz score

Not sat

Games

Not played

Points this lesson

0

Best run

0 in a row

Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?

Ask Luna

Do the work

Your written work for this lesson

This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.

Article

How a supermarket checkout knows the price

When a barcode is scanned, the checkout does not store the price itself. It sends the barcode number to a database and reads back a record: product name, price, whether it needs an age check. The record is the single place the price lives, so changing one row changes every till in the shop at once.

Problems come from bad data, not bad scanners. If two products share a barcode, or a price update reaches the shop overnight but the till holds an old copy in its cache, customers are charged the wrong amount. Shops check this with test transactions: scan a known item, expect a known price, record what actually happened.

Good systems also log every scan. If a customer complains, the log shows exactly which record was used and when.

Written for Good Learning Co.

Reading questions

  1. Write in your own words what the checkout sends and what it receives back.
  2. Explain one way bad data could cause a wrong price, and how logging helps find it.
  3. Design a test table with four tests for a new checkout, with expected and actual results.

  • Reading and notes

    Reading

    Read the lesson text again and note the key terms and how each one is used, in your own words — as you would for revision.

    Half a page of notes

  • Extended writing

    Writing

    Explain a real system that uses this idea — how it works, where it can go wrong, and how you would make it safer or better.

    250–350 words

  • Algorithm on paper

    Diagram

    Write your steps out as pseudocode or a flowchart before you type anything, then photograph it.

    1 flowchart or 10 lines

  • Code write-up

    Writing

    Copy your code in, then explain underneath what each part does and what you had to fix.

    Code + 5 sentences

  • Test table

    Working out

    Make a test table: what you tried, what you expected, what actually happened.

    4–6 tests

Saved as you type.

Part 1 of 19 · Introduction

How this is going

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    Understand how computer networks, including the internet, can provide multiple services such as the World Wide Web

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