Skill: course-build → write-lesson → atomise (proposal only; the coordinator edits the register) @ a5ff054
Topic 16 — atom proposals (28 September 2026)
In plain words. One split is proposed. Olivia asked that sorting be taught with a GIVEN property first and then a CHOSEN one. Those are two different skills a child can pass and fail separately: putting buttons into a red pile and a blue pile when told "by color" is a one-step routine; looking at six white shells and working out that color cannot sort them, so size must, is a judgement with its own trap (trying to sort by a property every object shares, and getting one group). L04 teaches the first, L05 the second. James (28 Sep 2026): "feel empowered to… split into separate atoms if you feel that a lesson is under atomised." The lesson is written under the provisional id below; the coordinator adds the atom to MAT3.json and renames.
| Field | Proposal |
|---|---|
| id | MAT3-P01 (provisional; slot between MAT3-002 and MAT3-003) |
| title | Choose a property to sort by |
| behaviour | Given a set of objects, choose a property that is different from object to object and sort them by it into two or more groups [e.g., six white shells, some big and some small: color puts them all in one group, so sort by size]. |
| sd / sdName | SD-1 / Properties you can observe and measure |
| type | Categorical |
| prereqs | MAT3-002 (sort by one GIVEN property), MAT3-001 |
| standards | FL SC.3.P.8.3 (the same row as MAT3-002; TEKS G3-6A's compare/sort clause) |
| cross | Split from MAT3-002 at authoring (Topic 16, 28 Sep 2026): Olivia's "first GIVE the property, then have the student CHOOSE one" is two skills. The rule: pick a property that differs from object to object; a property that is the same for every object puts them all in one group. Feeds MAT3-003 (ordering needs a property with a least and a most — the same judgement one step on). |
| misconception (SD-1 list) | belief: "Any property can sort any set." · origin: induced · counter: try color on six white shells — one group, no sort; try size — two groups · trap: choosing "their color" as the property that sorts a set of all-red apples. |
| downstream | MAT3-003's prereq becomes MAT3-P01 (was MAT3-002). The feeds68 row MAT3-002 → MAT-005 is unchanged. |
Why not leave it inside MAT3-002. With both in one video the "choose" step got two beats of a 150-word script; the PP100 type that tests choosing (type 6, "which property can sort these") is a different design move from type 5 ("which property WERE these sorted by"), and the coverage table wants an atom to hang it on. Small atoms are what James asked for ("PP100s on quite granular stuff is absolutely fine").
No misconception atom is proposed. The two misconceptions the topic meets — "observing means looking" and "what I think happened is part of what I saw" — are SR3-001's and SR3-002's own counters and are taught inside those lessons. "A right idea is still an idea about it" is written into L02 (Kirra's idea "might be right, might be wrong") and tested by a TRUE claim item, not split out.
Non-author review, 28 Sep 2026 (REVIEW_G3T16_2026-09-28.md, decision 2): approve, with "into two or more groups" in the behaviour so the atom is not read as two-group-only. Applied above; the coordinator's ruling: MAT3-P01 stays proposed.