What is a Computer Network? Connecting Devices Together

Grade 5 (Primary 5) Term 1 • Week 1

About 35 minutes

Have you ever wondered how an ATM machine at a bank in Lagos or Abuja can check how much money is in an account opened in Enugu? Or how your school teacher can send an examination timetable to thirty computers in the ICT lab at the same time?

None of this happens by magic. It works because computers are connected together into computer networks. In this lesson, we will explore what a network is, how computers talk to each other, and why networking makes computing so powerful.

Learning Outcomes

By the end of this lesson, you will be able to:

Define what a computer network is using clear everyday words.
Explain three key benefits of connecting computers: resource sharing, communication, and centralized storage.
Distinguish between a standalone computer and a networked computer.
Identify common hardware and software resources that can be shared across a network.

Prerequisite Knowledge

Before starting, you should: - Know the main parts of a computer (monitor, keyboard, mouse, system unit) from Primary 4. - Understand that computers process data and save files onto storage media like flash drives.

Key Vocabulary

Term	Simple Meaning
Computer Network	Two or more computing devices linked together by cables or wireless signals to share data and equipment.
Standalone Computer	A computer that operates alone and is not connected to any other computer.
Resource Sharing	Letting multiple computers use a single piece of hardware (like a printer) or software program.
Data Transmission	The electronic movement of information from one device to another across a network.

1. Standalone vs. Networked Computers

Imagine you are sitting in a classroom writing a story on a computer. If nobody else's computer can see your story, and you have to copy it onto a plastic USB flash drive and walk across the room to give it to your teacher, your machine is a standalone computer. It stands all alone!

[ Standalone PC A ]                         [ Standalone PC B ]
  (No connection)                             (No connection)
       |                                             |
       +---> Must walk with a USB flash drive <------+

Now imagine an invisible or physical bridge connects your computer directly to the teacher's computer. When you finish your paragraph, you click Save to Class Folder, and the teacher sees it appear on their screen instantly. Your computer is now a networked computer!

[ Student PC 1 ] ----+
                     |
[ Student PC 2 ] ----+---> [ Network Switch / Wi-Fi ] ---> [ Teacher's PC ]
                     |                                              |
[ Student PC 3 ] ----+                                     [ Shared Printer ]

2. Why Do We Build Networks?

Computer networks provide four major benefits in schools, hospitals, and businesses:

Hardware Resource Sharing: Instead of buying a printer for every single computer in a school, the school buys one high-speed printer, connects it to the network, and all fifty computers can print to it.
Instant Communication: Users can send messages, audio files, and classroom notices across the building in seconds.
Central File Access: Learning notes and textbooks can be stored on a central school computer so students can read them from any computer in the lab.
Internet Sharing: One internet connection coming into a school building can be shared across all teachers' laptops and student tablets.

Worked Example: The School Library Dilemma

Problem: Green Valley Primary School has a computer lab with 20 desktop computers. The head teacher wants students to be able to print their weekly social studies essays. A laser printer costs ₦120,000.

Option A (Standalone): Buy 20 small printers—one for each desk. Total cost: 20 × ₦50,000 = ₦1,000,000.
Option B (Networked): Buy 1 fast shared laser printer (₦120,000) and connect all 20 computers to a local network switch with cables (₦40,000). Total cost: ₦160,000.

Analysis: Option B saves the school ₦840,000! Furthermore, the teacher only needs to buy ink toner and paper for one machine instead of maintaining twenty separate machines. This shows why resource sharing is central to modern technology.

Practical Class Activity: The Human Network Simulation

You do not need a computer lab to understand how networks transfer data! We can model a network right in our classroom.

Materials:

4 index cards or paper sheets (labelled Computer A, Computer B, Computer C, and Network Hub).
2 pieces of string or yarn (representing network cables).
A handwritten note: "Good morning! What time is break?"

Instructions:

Student 1 holds the card Computer A.
Student 2 holds the card Network Hub in the center of the room.
Student 3 holds the card Computer B.
Connect Student 1 to Student 2 with one string, and Student 2 to Student 3 with the other string.
Student 1 wants to send the message to Student 3. Student 1 hands the folded note to the Hub (Student 2).
The Hub inspects the destination label ("For Computer B") and passes it along the second string to Student 3.
Student 3 writes the reply ("Break is at 11:00 AM") and sends it back through the Hub.

Expected Observation:

Data does not jump through thin air by magic; it follows a defined transmission path through an interconnecting node.

Common Mistakes & Corrections

Common Mistake	Why It Is Incorrect	Proper Correction
"A computer is networked just because it has electricity plugged in."	Power cables only supply electrical current; they do not carry computer data.	A computer is only networked when it is connected to a data link (Ethernet cable or Wi-Fi).
"If one computer on a network breaks down, all computers turn off."	Individual computers still have their own processors and power supplies.	In standard networks, if one workstation turns off, the other computers continue working.
"The internet and a network are the exact same thing."	The internet is just one very large global network.	A network can be as small as two computers in one bedroom with no internet access at all.

Notebook Summary

Copy Into Your Computing Notebook

A computer network is a collection of two or more computers connected together to share files, equipment, and internet access.
A standalone computer works by itself without any connections.
Networks save money through resource sharing (such as sharing one printer among twenty students).
Networks allow fast, safe communication between classrooms and offices.

Extension Challenge

Walk around your home or school and make a list of all devices that connect to the Wi-Fi or have a network cable plugged in (e.g., smart television, decoder, laptop, smartphone, POS terminal). Write down what resource each device is using over that connection!