Driverless Racetrack Algorithms

Overview

Students design, sequence and test a physical algorithm to guide a rider around a taped racetrack without hitting walls or “oil spills”. Through an unplugged Technology activity, they practise decomposition, precise instructions, testing and debugging, while learning that an algorithm must be checked in order before it is launched.

Learning intentions

• WALT design and test a step-by-step physical algorithm to guide a rider around a racetrack.
• WALT use forward steps, left and right steps, and 90-degree turn symbols.
• WALT test instructions from start to finish and debug any errors.
• WALT explain how careful sequencing improves a technological solution.

Success criteria

• I can map out a pathway using forward arrows and 90-degree turn symbols.
• I can follow my instructions from start to finish.
• I can spot a wrong turn or obstacle and change the correct instruction.
• I can explain how testing helped improve my algorithm.

Curriculum links

• Technology — designing and developing outcomes through purposeful planning, testing and improvement.
• Technology — computational thinking: breaking a problem into manageable steps and creating an ordered algorithm.
• Technology — communicating design ideas using symbols, diagrams and precise language.
• Supports the refreshed curriculum emphasis on practical problem-solving, collaboration, iterative design and explaining decisions.

Lesson structure (60 minutes)

1. 0–10 min · Warm-up: The Driverless Racebike. Open with the driverless racebike hook and explain that a racebike has no human brain and does exactly what its code tells it to do. Act as the “racebike” and invite a student to give an instruction such as “turn”; spin continuously until the class improves it to “turn 90 degrees right, then move forward two grid spaces”. Introduce algorithm, decomposition, bug or “oil spill”, and debugging or “pit stop fix”. Students suggest why vague instructions cause problems and practise showing a 90-degree turn with their bodies.

2. 10–18 min · Model precise sequencing. Display the algorithm modelling slides and show a simple 4 × 4 racetrack with a start, finish and one oil spill. Think aloud: “First I decompose the journey into small actions. Next I put the actions in order. Finally I test them.” Model the directional cards and symbols: forward step, turn left 90°, and turn right 90°. Deliberately place one card incorrectly, invite students to predict the crash, and demonstrate a “Pit Stop” debug. Students rehearse the sequence orally with a partner using “first, next, then, finally”.

3. 18–23 min · Organise teams and plan. Place students in groups of three and use the group role cards to assign rotating roles: Chief Engineer, Test Rider and Pit Crew Debugger. Distribute the unplugged floor racetrack planning sheet to each group. Students mark or discuss the start and finish, identify hazards, and lay out a proposed sequence of arrow cards before anyone steps onto the track.

4. 23–45 min · Human Racebike Navigators. Set up the taped floor grids with black oil-spill tiles and remind students that the Test Rider may follow only the instructions that have been placed in order. The Chief Engineer lays out the physical cards, the Test Rider wears the helmet or holds the handlebars and moves one grid space at a time, and the Pit Crew Debugger watches for an oil spill, wall or wrong turn. When an error occurs, the debugger calls “Pit Stop!”, names the problem, and helps replace the smallest possible part of the sequence. Groups test from start to finish, record successful changes on the planning sheet, then rotate roles so each student experiences all three responsibilities. Circulate and ask: “Which instruction caused the problem?”, “How do you know?”, and “What will you change for the next test?”

5. 45–52 min · Share a debugged solution. Bring students to the mat and open the testing and reflection slides. Invite one group to demonstrate an “oil spill crash”, identify the incorrect arrow and show the corrected sequence. Other students use thumbs up, sideways or down to indicate whether the fix is likely to work, giving one reason based on the order of instructions.

6. 52–60 min · Whiteboard check and reflection. Display a mini 3 × 3 track with an oil spill. Students independently draw or write a four-step sequence on mini whiteboards to guide a rider around it, including at least one 90-degree turn, then hold boards up for a quick check. Finish with the exit ticket strips: students state one thing they learned about algorithms and one way they debugged. Collect planning sheets and note students who confuse turning with moving, need support with spatial language or can independently explain a correction.

Resources

• the driverless racebike and algorithm slide deck
• the unplugged floor racetrack planning sheet
• the group role cards
• Painter’s tape or foam floor grid mats forming 4 × 4 or 5 × 5 tracks
• Printed directional arrow cards: forward, turn left 90°, turn right 90°
• Black paper “oil spill” obstacle tiles
• Toy handlebars or helmet props
• Mini whiteboards and markers
• Exit ticket strips

Assessment

• Observe planning, sequencing and role participation during group work; ask students to justify which instruction caused an error.
• Check planning sheets for a complete pathway, correctly ordered symbols and evidence of a tested change.
• Use the whiteboard task and exit ticket to identify students who understand 90-degree turns, sequencing and debugging, and those requiring further spatial support.

Differentiation

• Support learners with a reduced 3 × 3 track, fewer obstacles, colour-coded cards, a visible model and sentence starters: “The bug is…”, “I will change…”, and “The rider must…”.
• Provide spoken and visual instructions, allow students to physically rehearse turns, and pair EAL learners with supportive peers. Use the group role cards to make responsibilities clear.
• For students needing additional support, allow a partner to point to each card while the Test Rider moves, or provide a partially completed sequence.
• Extension: offer the Blind Test Rider Challenge. The rider wears a visor and moves only from shoulder taps: one tap means forward, left shoulder means turn left, and right shoulder means turn right. Groups may also attempt a Multi-Rider Relay, sharing a larger grid while avoiding collisions and oil spills.