Hour of Code lesson for KS3 Computer Science: unplugged robot, algorithm and binary activities plus six Python turtle and quiz challenges, with solutions.

A ready-to-teach coding hour for Computer Science Education Week (7–13 December 2026), written for ages 11 to 14 and for teachers who have never taught coding. Pupils start away from the screen, programming a partner like a robot, then write real Python in a free browser editor that needs no login. Every answer is revealed on click, and every program has been run and checked.

What pupils do

• Program the robot: write F, L and R commands to steer a robot round a grid to a star, avoid rocks, then find and fix a bug in a broken program.
• Sort the algorithm: put eight shuffled steps for making toast in order (the letters spell a computing word) and spot the step that makes a decision.
• Binary bracelet: decode letters stored as five beads, then colour a bracelet with their own initials in binary.
• Six Python challenges, easy to stretch: Say hello (input and print), Turtle square (for loops), Turtle star (angles), Computer quiz (if and else, keeping score), Guess my number (random numbers and a while loop) and Turtle snowflake (functions).

What’s included

• PowerPoint (27 slides, 16:9): what coding is, the three unplugged activities, a task slide and a click-to-reveal solution slide for each Python challenge, a recap, an editable certificate and a credits slide. Speaker notes on every slide explain what to say and do.
• Unplugged activity cards (PDF, A4, 7 pages): robot command cards, three robot grids with program boxes, a design-your-own grid, toast sorting cards and the binary bracelet sheet with a full A–Z code table.
• Python challenge sheet (PDF, A4, 4 pages): website links, tips, a progress tracker and the starter code for all six challenges.
• Teacher solutions (PDF, A4, 8 pages): a 55-minute lesson plan, set-up checklist, common Python errors and fixes, every unplugged answer, and each program’s full solution with its expected output (text output or the finished drawing).
• Hour of Code certificate (PDF, A4 landscape) to print and fill in.

How to use it

Allow 5 minutes for “What is coding?”, 15 for the unplugged activities, 30 for Python and 5 for certificates. Pupils work in pairs for the unplugged tasks, then through the Python challenge sheet at their own speed; use the solution slides to check work together. Text challenges run on and the turtle challenges on coddy.tech/playground/turtle (both free, no login); any browser Python that supports turtle and input() works. Please check the sites open on your school network before the lesson. No computers? Run all three unplugged activities and trace the Python programs on paper.

“Hour of Code” describes the activity only; this resource is not made by or connected with .

Last updated: November 2026