JSS 1 Second Term

Lesson objectives

By the end of the week, learners should be able to:

1. Name the eight major parts of a desktop system unit and give each a function.
2. Explain what the CPU, RAM, ROM, expansion slots, cooling fan and power supply do together.
3. Describe why a new expansion card must fit the motherboard.
4. Identify whether a given add-on belongs inside or outside the case.
5. Build or inspect a system unit diagram from a set of real or picture parts.

Key vocabulary

• System unit: the metal or plastic box that holds the processor, memory, drives and power.
• Motherboard: the main circuit board that connects every component.
• Processor: the chip that carries out instructions; sometimes called the brain.
• RAM: temporary working memory that holds data and programs currently in use.
• ROM: permanent read-only memory that holds programmes such as BIOS.
• Expansion slot: a slot on the motherboard that lets extra hardware attach.
• Power supply: converts mains electricity into lower-voltage DC electricity.
• Cooling fan: moves air to carry heat away from hot chips.
• Heat sink: passive metal fins that help remove heat without moving air.

Common misconceptions

• "The fan is optional on a desktop." A fan or heat sink is required because processors get warm and overheat without active cooling.
• "A bigger case always makes a faster computer." Case size does not change speed; component quality and software matter more.
• "Expansion cards connect anywhere." Cards must physically fit the matching motherboard slot type.

Teacher activities

1. Starter: open a system unit if one is available and remove the CPU, memory stick and fan so the class sees the empty interior layout.
2. Name each part and state its function as you point to each, writing the name next to each drawing on the board.
3. Explain the CPU as the manager, the RAM as temporary working space and the ROM as the permanent basics.
4. Compare the power supply as an electricity converter and the fan as an active cooler for the others.
5. Set a card-sorting task: picture cards must be matched to part labels, then justify two placements aloud.
6. Close with an image of a laptop thermal design where the parts have been simplified, and ask learners to locate the same parts in a laptop.

Student activities

1. Handle the opened system unit and name each removable part.
2. Label a blank eight-part diagram with functions in their own words.
3. Sort the picture cards into matching part names, explaining each match.
4. Complete a statement: "RAM holds programs in use until the power is turned off."
5. Decide whether a given add-on belongs inside or outside the case, with a reason.
6. Answer the exit question: "Why is the cooling fan important even in small cases?"

Practical / learning evidence

A completed labelled system-unit diagram with eight parts and their functions, plus a sorting chart that places picture cards under correct part names and a one-sentence explanation of the cooling role.

Resources and preparation

An actual desktop system unit (open safely), pictures of each component, blank diagram and card sets. If no machine is available, use prepared photographs and the diagram template. Keep a screwdriver and anti-static precautions out of learners' reach.

Assessment for learning

Check the labelled diagram for at least six correct entries; one or two students may need reteaching before full credit. Ask two learners to explain the CPU role without notes. Mark the sorting chart for correct matches with reasons.

Inclusion and homework

Provide a partially completed diagram for learners who need scaffolding and allow written rather than verbal explanations. Extend confident learners by asking which part acts like a traffic controller on the motherboard. Homework: list three additional parts found only on a laptop and state their role.