Lesson Plan: Designing an Algorithm to Solve Everyday Problems

Unit Theme: Computer Science Foundations
Grade Level: Middle School (6–8)
Length: 2 class periods
Framework: Design Thinking + Computational Thinking + Makerspace

Essential Question:

How can we design step-by-step instructions that help computers (and humans) solve problems?

  • Objectives

    Students will:

    * Understand what an algorithm is

    * Practice computational thinking (decomposition, pattern recognition, logical steps)

    * Use the design thinking process to design a problem-solving system

    * Build a physical model of an algorithm

  • Key Concepts

    Students learn:

    Algorithm
    A step-by-step set of instructions for solving a problem.

    Input
    Information given to the system.

    Process
    The steps the system follows.

    Output
    The final result.

  • Materials (Makerspace)

    Students create a physical algorithm prototype.

    Possible supplies:

    * index cards

    * sticky notes

    * poster paper

    * arrows or string

    * cardboard

    * markers

    * colored stickers

    * simple switches or LEDs (optional)

Lesson Structure Using the Design Process

1. Empathize

Scenario Activity

Students discuss situations where clear instructions matter.

Examples:

  • following a recipe

  • giving directions

  • organizing schoolwork

  • sorting recycling

Ask students:

  • What happens when instructions are unclear?

  • Why do computers need very precise instructions?

Students identify how algorithms help solve everyday problems.

2. Define

Students write a problem statement.

Examples:

Students often forget the order of steps when getting ready for school.

Other possible problems:

  • sorting recycling correctly

  • organizing homework priorities

  • determining lunch lines efficiently

  • choosing which book to read next

Each group chooses one problem to solve using an algorithm.

3. Ideate

Students brainstorm possible step-by-step solutions.

Students sketch two possible algorithm solutions using.a flowchart design.

Encourage them to think about:

  • inputs

  • decisions

  • outputs

4. Prototype (Makerspace)

Students build a physical algorithm model.

Option 1: Human Algorithm Path

Students create a decision pathway on the floor using arrows and cards.

Example:

Start → Check homework → Check difficulty → Choose task

Students physically walk through the algorithm.

Option 2: Sorting Machine

Students design a cardboard sorting machine.

Example systems:

  • recycling sorter

  • homework priority sorter

  • library book organizer

Input cards go into the machine and follow branching paths.

Option 3: Flowchart Board

Students build a large visual flowchart using:

  • index cards

  • arrows

  • colored paths

This shows the algorithm clearly.

5. Test & Improve

Students test their algorithm using new scenarios.

Example:

Homework tasks:

  • Math due tomorrow

  • Science due next week

  • History quiz Friday

Students see if the algorithm makes consistent decisions.

They revise steps if needed.

Ethics Discussion

Students discuss:

  • What happens when algorithms make mistakes?

  • Who is responsible for designing good algorithms?

  • Why should algorithms be clear and transparent?

Students reflect on how poor instructions can create unfair or confusing outcomes.