Inside the Computer
The big box of a desktop computer is called the system unit. All the working parts sit inside it. You cannot see them without opening the box, but they work every second the computer runs.
🏠 Parts Inside the System Unit
| Part | Full Name | Job |
|---|---|---|
| CPU | Central Processing Unit | Runs all programs and tasks |
| RAM | Random Access Memory | Holds active tasks for now |
| HDD / SSD | Hard Disk / Solid State Drive | Stores all files permanently |
| Motherboard | Motherboard | Connects all parts together |
| Power Supply | PSU | Sends electricity to all parts |
How RAM and the Hard Disk Work Together
RAM stores things only while the computer is on. The hard disk stores things even after you switch it off.
🔄 RAM vs Hard Disk
💭
RAM
Holds open programs right now
⚡ Clears when power is off
💾
HARD DISK
Stores all your files long-term
✅ Keeps files after power off
The Motherboard Connects Everything
The motherboard is a flat green board inside the system unit. Every part plugs into it. The CPU, RAM and hard disk all connect through the motherboard so they can communicate.
🔗 Motherboard Connection Diagram
🧠 CPU
↔
MOTHERBOARD
↕
↔
💾 Hard Disk
💭 RAM
Example: A classroom has a teacher (CPU), a whiteboard (RAM) and a cupboard (hard disk). The classroom floor connects everything — just like the motherboard.
✏️ Exercise
| # | Question |
|---|---|
| 1 | What does CPU stand for? |
| 2 | Which part clears when the computer is switched off? |
| 3 | What does the motherboard do? |
| 4 | Name the part that stores files permanently. |
| 1. | Central Processing Unit |
| 2. | RAM |
| 3. | It connects all parts inside the computer together |
| 4. | Hard Disk (HDD or SSD) |
Quick Review
| Question | Answer |
|---|---|
| Where do all the internal parts sit? | Inside the system unit |
| Which stores files permanently? | Hard Disk (HDD or SSD) |
| What connects CPU, RAM and HDD? | Motherboard |