Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Computer Science
Lesson Topic: Show understanding of the purpose of interrupts
Learning Objective/s:
  • Describe what an interrupt is and how it alters the normal instruction flow.
  • Explain why interrupts are needed for responsiveness, efficiency, and multitasking.
  • Identify the main types of interrupts and their typical sources.
  • Outline the sequence of steps the CPU follows to handle an interrupt.
  • Evaluate the benefits of using interrupts compared with polling.
Materials Needed:
  • Projector or interactive whiteboard
  • Slides/diagram of the fetch‑decode‑execute cycle with interrupt overlay
  • Sample ISR code snippets (e.g., C or Arduino)
  • Handout summarising interrupt types and handling steps
  • Laptop with IDE/simulator for live demo
  • Worksheets for quick quiz and matching activity
 Introduction:
Begin with a quick poll: “What happens when you press a key on the keyboard?” Connect this to prior learning about the fetch‑decode‑execute cycle and explain that the CPU can pause that cycle to respond instantly. State that by the end of the lesson students will be able to describe interrupt handling and compare it with polling.
Lesson Structure:
  1. Do‑now (5') – Students answer the poll question on sticky notes; teacher collects responses.
  2. Mini‑lecture (10') – Review the fetch‑decode‑execute cycle, introduce the definition and purpose of interrupts; display a diagram.
  3. Guided exploration (12') – Present a table of interrupt types; students work in pairs to match real‑world examples to each type.
  4. Demonstration (10') – Live coding of a simple ISR in a simulator, highlighting context save/restore.
  5. Collaborative activity (10') – Groups create a flowchart of the 7‑step interrupt handling process; teacher circulates to check understanding.
  6. Formative check (5') – Quick Kahoot quiz on benefits of interrupts versus polling.
  7. Wrap‑up (3') – Recap key points; exit ticket: write one everyday device that relies on interrupts.
Conclusion:
Review the main steps of interrupt handling and the advantages over polling. Collect the exit tickets where students name a real‑world device using interrupts. For homework, ask learners to research how timer interrupts enable multitasking in an operating system and prepare a short written explanation.