Year 1 · 40 minutes · Patterns
Can two different rules explain the same beginning?
A short pattern gives clues, but it may fit more than one rule. Red, blue, red, blue might repeat forever, or a rule might change after four beats. We test by finding a place where the rules make different predictions. A good explanation says which rule it uses and what evidence could show it is wrong.
Prepare red and blue counters, a strip numbered 1–12 and two rule envelopes: repeat AB; repeat AB for four beats then AA. Keep the second rule hidden until the counterexample.
Continue a repeating two-symbol pattern. Useful earlier investigations: f-sort Use pairs: one child chooses or points while the other traces or checks. Swap after one case. An adult records the child’s words; drawing and movement are equally valid evidence.
Australian Curriculum Version 9 · Digital Technologies: AC9TDI2K02, AC9TDI2P02. Selected aspects only. This activity contributes evidence; it does not cover the full descriptor or achievement standard. A programming descriptor is not claimed for merely moving controls. ACARA AI curriculum connection · V9 Technologies These are planning connections, not ACARA endorsement or exhaustive descriptor alignment.
Clap tap–rest–tap–rest and invite the next beat. Do not announce that there is only one answer.
Ask: “What rule are you using?”
Listen for: “Tap and rest keep repeating.”
Display two possible rules. Children mark beat 5 for each before extending the ribbon.
Ask: “Will these rules always agree?”
Listen for: “They agree at the start, but maybe not later.”
Edit the repeating unit and reveal the ribbon one beat at a time. Keep the seed sequence fixed while comparing both rules.
Ask: “Which is the first beat that could tell the rules apart?”
Listen for: “The beat where one says rest and the other says tap.”
Activate the rule that changes after the shared prefix. Trace why the earlier observations did not exclude it.
Ask: “Was our first rule silly, or did we need more evidence?”
Listen for: “It fitted what we had, but we needed another beat.”
Partners write two rules with the same first four beats. Exchange a proposed test position and justify it.
Ask: “Would looking at beat 2 help?”
Listen for: “No, both rules say the same there.”
Collect both rules, test position and observation.
Ask: “What would change your mind about the rule?”
Listen for: “Seeing a beat my rule does not predict.”
A few examples prove the only rule.
Write both rules’ predictions for beat 6 before extending the visible pattern.
A rule can repeat AB for four beats and then switch. It matches the beginning perfectly but disagrees later.
Create two matching beginnings and choose the earliest observation that distinguishes their rules.
Check the selected test is a disagreement, not merely a later beat. Ask learners to run each rule with counters if they cannot explain the difference.
Use audible beats and tactile counters; compare only six positions. Adult records rule descriptions.
Invent a third rule consistent with all observed beats. Discuss why we prefer some explanations while remaining open to revision.
A two-rule pattern strip with a marked distinguishing test.
Patterns use synthetic colours and beats. Offer a silent version and avoid loud clapping for sound-sensitive students.
Evaluate repeating four-bit programs against switched continuations over twelve beats; count the first distinguishing beat. The larger workload repeats the finite rule set and cannot prove infinite behaviour.
| Criterion | Beginning | Secure | Extending |
|---|---|---|---|
| Rule description | Copies visible beats | Names a repeat unit | Describes the repeat and switch condition |
| Test design | Chooses an agreeing beat | Finds a disagreeing beat | Explains why earlier observations cannot decide |
Australian Curriculum Version 9 · Digital Technologies
References: AC9TDI2K02, AC9TDI2P02. Read the current source (checked 2026-09-07).
Evidence to assess: A two-rule pattern strip with a marked distinguishing test.
Selected aspects only. This activity contributes evidence; it does not cover the full descriptor or achievement standard. A programming descriptor is not claimed for merely moving controls. Moderate the supplied illustrative responses against your school unit and current achievement standard.
These are planning estimates to test with your class. A short session develops one supported claim; it does not compress the whole senior project.
| Stage | 45 minute focus | 60 minute investigation |
|---|---|---|
| Readiness and prediction | 0–5 | 0–5 |
| Trace the supplied example | 5–13 | 5–15 |
| Author and run cases | 13–25 | 15–35 |
| Counterexample and redesign | 25–35 | 35–45 |
| Explain and discuss | 35–42 | 45–55 |
| Export and handover | 42–45 | 55–60 |
For a longer project, use three 50-minute sessions. Session 1 (0–50): readiness, model, hypothesis and initial cases. Export a project and record the next test. Session 2 (50–100): reopen, check settings, author counterexamples and revise the design. Export the changed project and identify unresolved evidence. Session 3 (100–150): independent peer test, final artefact, individual explanation and moderation. If using two 60-minute sessions, stop at minute 60 after saving the first comparison; use 60–120 for redesign, independent test and defence.
Entry check: Continue a repeating two-symbol pattern. Ask the learner to demonstrate it before choosing the level of support.
Preparation: allow about 10 minutes to run the starter, print the cards and check a project can be reopened. This estimate has not yet been measured in a classroom pilot.
For young learners, show one picture or case at a time. Accept pointing, movement, a drawing or adult transcription. Read the question aloud; explain the numeric model privately to the adult. Do not assess keyboard speed or independent reading.
For one device, use a projector: one pair predicts, one operates, and the class records on paper. Swap roles after the first comparison. For individual access, support keyboard controls and a written table equivalent to each visual. Learners may explain orally or with an annotated diagram. Never require personal data, a recorded voice, or a photograph.
Mixed readiness: if the entry check is difficult, use the linked prerequisite and the first two case cards; retain the same central question. If secure, ask the learner to design an unseen test and state which explanation it could disprove.
Repeat each symbol string and compare one beat at a time.
Starting parameters: Beats to compare = 12
3 cases calculated from your supplied inputs. Compare the evidence with your prediction.
| ruleA | ruleB | first different beat |
|---|---|---|
| AB | ABABAC | 6 |
| AAB | AABAAB | No difference in this window |
| ABC | ABCD | 4 |
These are authored examples, not work collected from children. Assess reasoning using the lesson rubric, not whether the first prediction was correct.
Beginning: “It worked because the result looks right.” This identifies no exact case, control or measurement. Ask the learner to point to one row and say what happened.
Developing: “In the first case I recorded ruleA: AB; ruleB: ABABAC; first different beat: 6.” This cites evidence, but does not yet explain how the result follows from the rule. Ask the learner to trace the relevant step.
Secure: “For the first supplied case, ruleA: AB; ruleB: ABABAC; first different beat: 6. I can trace it using this mechanism: Repeat each symbol string and compare one beat at a time. My result supports a claim about these supplied cases. It does not establish that the same result holds outside them.” Look for an accurate trace, the actual settings and a bounded claim; accept equivalent oral or visual evidence.
Extending: The learner constructs and reruns a new case, reports whether the first explanation survives, and defends a revised design. Use this concrete challenge: Create two rules with the same beginning. Give a partner the beginning and ask what evidence would distinguish them. Require the original and changed evidence and this boundary: Matching a finite beginning does not prove two patterns will always match.
Moderation: first assess independently against each lesson criterion. Compare the exact trace or artefact that led to your judgement. Resolve differences using evidence, not polished language. Keep each learner's individual explanation even when the artefact was produced in a group.