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Study skills · Ages 7–9 · 50 minutes
Algorithms without a computer
Children write a clear, ordered set of instructions (an algorithm) to complete a task, test it, and debug it when it goes wrong.
Success criteria
- I can explain what an algorithm is
- I can write precise instructions in the right order
- I can find and fix a bug in an algorithm
Key vocabulary
- algorithm
- instruction
- sequence
- precise
- order
- bug
- debug
- test
- program
- robot
You will need
- a large floor grid (masking tape or a 5×5 chalk grid)
- arrow cards (forward, turn left, turn right)
- a soft toy as the "treasure"
- squared paper
- pencils
Practice sheets
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The Robot Helper
Maze
Maze
Computers do exactly what they are told, which is very different from what we mean. This lesson turns the teacher into a very literal robot, so children discover for themselves why instructions need to be precise and in the right order. No screens are needed.
1.Starter
5–10 minAnnounce: "Today I am a robot. I can only do exactly what you tell me." Ask the class to instruct you to sit down on a chair. When someone says "Sit down", sit on the floor next to the chair. When they say "Walk to the chair", walk straight into it gently and stop. Let the laughter happen, then ask: "Why did that go wrong?" Seven minutes.
2.Teach
10–15 minExplain: "An algorithm is a set of step-by-step instructions to do a job. Recipes, the steps for brushing your teeth and the directions to school are all algorithms. Computers follow algorithms called programs."
Model writing a good algorithm on the board for something simple, like drawing a square on squared paper:
- Put your pencil on a dot.
- Draw a line 3 squares to the right.
- Draw a line 3 squares down.
- Draw a line 3 squares to the left.
- Draw a line 3 squares up.
Script: "Every step is clear, and the order matters. What would happen if I swapped steps 2 and 4?" Then introduce bugs: "When an algorithm has a mistake, we call it a bug. Finding and fixing it is called debugging. Every programmer debugs, all the time."
robot
computer
blocks
puzzle
