alphaPlan · Programming facilitator notes
Predict, run, debug, create
Reference lesson: Programming in a Data World > Getting started > Turtle graphics and variables
Outcomes
- • Reach a visible first Python/Turtle run
- • Predict and trace movement before execution
- • Connect one variable change to output
- • Use a NameError to form and test a hypothesis
- • Create and revise a bounded personal drawing
Timing and materials
- • 60 minutes only when Python/Turtle and files are preflighted; timed 35-minute alternative
- • One working computer per learner or pair; printed reasoning sheets for waiting learners
- • Python 3/IDLE, supplied files, learner sheets and pens
- • Projector optional
60-minute delivery sequence
Preflight required: Python 3, IDLE, Turtle and both supplied files must work before the session. If they do not, extend the session or use the shared-device/print contingency below.
- 0·10 min. Open the supplied starter and reach the blue 80-pixel line. Confirm the prepared setup; do not attempt individual installations during this segment.
- 10·20 min. Learners trace and commit the L-shape prediction before execution. Run once and compare without grading the prediction.
- 20·30 min. Change only distance to 120. Ask which output changed, which stayed fixed and which line caused each.
- 30·42 min. Run the broken file. Require the last error line, failing line and one hypothesis before revealing the spelling comparison.
- 42·58 min. Learners build one bounded personal drawing in milestones, running after the first three moves and revising one observed result.
- 58·60 min. Debrief one cause-and-effect change and one debugging decision.
35-minute timed alternative
0-5 baseline; 5-10 predict/observe; 10-15 modify; 15-23 repair NameError; 23-32 three-move creation; 32-35 causal reflection. It omits installation troubleshooting, extended discussion, colour polish, a second creation revision and the full debrief.
Pair programming
- • Driver types and runs; navigator predicts, traces, reads errors and proposes one test
- • Swap after the baseline, debugging repair and first creation run
- • Driver explains the navigator's proposal before typing, so one learner cannot take over
Shared-device continuity
- • Pair learners on working devices; waiting learners become navigator or test lead with the print sheet
- • Rotate at the baseline, debugging and creation milestones
- • Treat administrator-blocked machines as unavailable, not learner error
- • Pause everyone only for a fault affecting many machines
Listen for
- • The first line is controlled by distance; the second reads distance // 2
- • The 90-degree turn is controlled independently
- • NameError means Python could not find a name
- • A useful fix makes definition and use agree
- • Creation explanation names one changed cause and visible effect
Compact troubleshooting
| Symptom | First check |
|---|---|
| Python not found | Try `py` on Windows; confirm Python 3 and reopen terminal |
| Wrong output/file | Save and verify the editor title before Run Module |
| Syntax/indentation error | Read line number; compare punctuation and leading spaces |
| No Turtle window | Use desktop Python/IDLE; keep turtle.done() last |
| Window seems frozen | Close the previous Turtle window before rerunning |
| Copied symbols fail | Retype quotes and minus signs in the editor |
| Administrator blocks installation | Stop repair attempts; use a prepared/shared device and print reasoning sheet |
Debrief and boundaries
- • An incorrect prediction is useful if the learner compares and revises.
- • Do not type the fix for a learner before they identify the failing line and hypothesis.
- • The local activity record is participation evidence, not proof that code ran or competence was verified.
Ask
- • Which line made the second segment half as long?
- • What did NameError let you rule out?
- • What did you improve only after seeing the first version?
Found something unclear, outdated or improvable? Suggest an improvement