Lesson Plan

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Lesson Plan
Grade: Date: 25/02/2026
Subject: Computer Science
Lesson Topic: Describe and use the process of stepwise refinement to express an algorithm to a level of detail from which the task may be programmed
Learning Objective/s:
  • Describe stepwise refinement and its role in algorithm design.
  • Decompose a problem into major sub‑tasks and refine them to detailed pseudocode.
  • Translate refined pseudocode into executable code and validate each step.
  • Evaluate refined steps for clarity, testability, and completeness.
Materials Needed:
  • Projector and screen
  • Whiteboard and markers
  • Printed handout of the refinement level table
  • Laptops with a Python IDE installed
  • Worksheet containing the vowel‑count exercise
  • Sticky notes for quick checks
 Introduction:
Begin with a short video clip showing a complex program broken into simpler parts to hook interest. Ask students to recall how they previously wrote algorithms and highlight any difficulties they faced. Explain that today they will learn a systematic top‑down method that ensures every step can be coded directly. Success will be measured by their ability to produce clear pseudocode ready for implementation.
Lesson Structure:
  1. Do‑now (5'): Quick quiz on algorithm terminology (algorithm, pseudocode, flowchart).
  2. Mini‑lecture (10'): Introduce stepwise refinement, show the four refinement levels with examples.
  3. Guided example (15'): Walk through the “find maximum” problem, refining from level 1 to level 4.
  4. Paired activity (15'): Students refine the insertion‑sort description using the handout and record each level.
  5. Whole‑class share (10'): Groups present their refined steps; teacher checks for ambiguity and completeness.
  6. Independent practice (15'): Worksheet – refine the vowel‑count problem to level 4 and write Python code.
  7. Exit ticket (5'): Write one advantage of stepwise refinement and submit on a sticky note.
Conclusion:
Recap the four refinement levels and how each adds necessary detail for coding. Collect exit tickets to gauge understanding and remind students to finish any unfinished refinement at home. Homework: choose a simple algorithm (e.g., factorial calculation), produce a full stepwise refinement to level 4, and bring the pseudocode to the next lesson.