Skill: course-build → write-mcqs → write-explanation, design-check-sequence @ 43d3060 · re-instanced after the non-author review (28 Sep 2026, night)
Topic 19 — Sinks, floats, sticks to a magnet: choosing materials — the PP100's ten question types, with their exemplars
What this page is. James approves a bank's question TYPES before the bank is generated (vault: A bank is reviewed as its question types first, one exemplar each, 28 Sep 2026). This sheet writes the exemplars in full, exactly as they sit in content/G3T19.py (PP100, flagged TYPE_SHEET_ONLY). Ten types for four atoms, one exemplar each. No other bank item exists yet. Once the types stand, about fifty items are generated from them, varying the objects, the materials, the tables and the names, easy-heavy.
James's rulings applied. Hard items are typed, never MCQs (28 Sep night): three text-entry types (the material that suits a floating job, read off a table; the property that suits a job; the floater's name, read off two tanks). Easy and medium are four-option MCQs. Every place-in-the-water, hanging-or-staying and table is DRAWN; no stem leans on a video; no option bundles a verdict with a reason; every stem is a positive question; no item figure carries a verdict chip; every table cell fits its column (figures.py asserts it); every typed accept list is generated by term_accept() (the term with its articles and "it is" / "being" forms), never hand-typed. Never cutlery as a steel example. "Density" is nowhere. Every exemplar is a fresh instance — the non-author review found four that were lesson checks renamed, and all ten were read again against every lesson case, quiz item, practice item and the intro (the list is at the foot).
How to read a type line. Each says what the stem asks, what the four options are (the kind of thing), and gives its exemplar scene. Every MCQ has a why (no per-option feedback in the bank; the engine prints Correct / Not quite). Tags follow depth of reasoning: easy = one thing read off one drawing or table; medium = a sort judged, the fair test's one variable picked, or a test result turned into a choice; hard = the name or the property PRODUCED (typed), two ideas held together.
The ten types
| Type | Item | Atom | Tag | Form | The stem asks… | The options / the accept | Exemplar scene |
|---|---|---|---|---|---|---|---|
| 1 | PP-1 | MAT3-007 | easy | MCQ, drawn table | four objects were tested in water: which one floated | four object names | Rocco's table: a tennis ball, a shell, an egg, a pebble |
| 2 | PP-2 | MAT3-008 | easy | MCQ | a magnet comes close to each of four objects, their materials named: which one does it pull | four objects with their materials | a glass jar, a cotton sock, a plastic ruler, a steel washer |
| 3 | PP-4 | MAT3-008 | medium | MCQ, drawn sort | a drawn sort into the two groups with one object misplaced: which object is in the wrong group | four of the drawn objects | Clem's sort: a steel spring sits in the does-not-pull box beside a cork and a glass marble |
| 4 | PP-3 | MAT3-060 | easy | MCQ, drawn table | four blocks tested the same way: which one stayed whole | the four blocks | Tuva's table: cement only, gravel only, cement and gravel, sand only |
| 5 | PP-5 | MAT3-060 + Topic 7's FOR3-007 (pair) | medium | MCQ | three lumps of a mix tested to see which dries hardest: which ONE thing should be different | four things that could differ (size, drying time, what they are made of, the push) | Iker's three lumps of papier-mâché |
| 6 | PP-6 | MAT3-008 + MAT3-061 (pair) | medium | MCQ, drawn table | a magnet-test table of four materials for a notice board that magnets must hold papers to: which material suits the board | the four materials | Dilan's table: cork no, steel yes, plastic no, aluminum no |
| 7 | PP-7 | MAT3-061 | medium | MCQ | a material suits a job (verdict in the stem): which property makes it suit | four single-statement properties | rubber for the handle grips of a bike |
| 8 | PP-8 | MAT3-007 + MAT3-061 (pair) | hard | text, drawn table | four materials tested in water for a toy sailboat that floats: type the name of the material that suits the sailboat | term_accept("wood") | Aisha's table: steel, wood, stone, glass |
| 9 | PP-9 | MAT3-061 | hard | text | a material picked for a fresh job with the job's need stated: type the property that suits the job | term_accept("see-through") + term_accept("clear") | glass for a greenhouse wall so light gets to the plants |
| 10 | PP-10 | MAT3-007 | hard | text, drawn tanks | two objects let go in two tanks: type the name of the object that floats | term_accept("plastic lid") + term_accept("lid") | a raisin (on the floor) and a plastic lid (at the line) |
Hard because (type 8): four rows are read, the one whose property (floats) matches the job's need is found, and its name is typed — two atoms held together and the answer produced, not recognised. Hard because (type 9): the property is produced, not picked, on a job the lessons never used (a greenhouse wall); the stem gives the need in plain words ("so that light gets to the plants") and the student names the property; "clear" is accepted as the everyday word a child writes — James's call whether it stays. Hard because (type 10): two drawn tanks are read, the floater found, and its name typed.
Coverage (every atom alone, and the pairs)
| Atom | Types testing it alone | Pair types |
|---|---|---|
| MAT3-007 sinks or floats | 1, 10 | 8 (with MAT3-061: the floating material for a sailboat) |
| MAT3-008 does a magnet pull it | 2, 3 | 6 (with MAT3-061: the material a magnet pulls, for a notice board) |
| MAT3-060 mix two materials | 4, 5 | 5 (with Topic 7's fair test: the one thing that changes) |
| MAT3-061 say why that material | 7, 9 | 6 (with MAT3-008); 8 (with MAT3-007) |
At most two alone-types per atom (James: "unlikely that you're going to need more than two question types per atom"). Order in the file: easy PP-1, PP-2, PP-3 → medium PP-4…PP-7 → hard PP-8, PP-9, PP-10. Keys of the seven MCQs, in file order: PP-1 A · PP-2 D · PP-3 C · PP-4 B · PP-5 C · PP-6 D · PP-7 B (one A, two B, two C, two D). Typed items: 3 of 10 on the sheet; in a bank of about fifty, types 8, 9 and 10 supply 12–15 typed items on fresh materials, jobs and objects.
Fresh instances (read against every lesson case, quiz item, practice item and the intro, 28 Sep night)
| Item | Instance | Nearest lesson-side use | Why it is fresh |
|---|---|---|---|
| PP-1 | Rocco's tennis ball, shell, egg, pebble | L01 q9 Nuria's table (lemon, key, sponge, egg) | a different four; one floater, not two sinkers |
| PP-2 | glass jar, cotton sock, plastic ruler, steel washer | L02's taught cases (paperclips, nail, block, cans); the L02 quiz's bolt, foil, screw, marble | none of these objects appears anywhere else in the topic |
| PP-3 | Tuva's cement, gravel, cement-and-gravel, sand | L03's bricks, the quiz's mud-and-straw and paper-and-glue tables; practice: plaster and sand | a fourth block, so no "none of them" closer |
| PP-4 | Clem's washer, hinge / cork, spring, marble | L02 q6 Isak's sort (rubber band misplaced); L02's cans and block | the objects and the misplaced one are new; the steel key ring was avoided because L02 q10 uses it |
| PP-5 | Iker's three lumps of papier-mâché, which dries hardest | L03 q9 Reuben's three bricks (the same move) | the same MOVE on a different make-and-test (a mask mix, not a brick) — James: reuse the lessons' types with different examples |
| PP-6 | Dilan's notice board; cork, steel, plastic, aluminum | L04 q9 a fridge door (aluminum / steel / wood) | a different job and a different row set |
| PP-7 | rubber for a bike's handle grips | L04 q6 Nour's claim (rubber for a bike tire); practice q5 (a tire) | a different part with a different need (the hands grip the bars) |
| PP-8 | Aisha's toy sailboat for the pond; wood over steel, stone, glass | L04 q7 a bath toy (cork over steel, stone); L04's raft line (wood suits a raft) | a different job, a different key (wood, from a drawn table), typed |
| PP-9 | glass for a greenhouse wall | L04's window (glass, see-through); L04 q5 a see-through cup | a fresh job with the need stated in plain words; the property produced |
| PP-10 | a raisin and a plastic lid | the intro's grape (its verdict spoken aloud) — replaced | the raisin is nowhere else in the topic; a raisin sinks in plain water |
The exemplars, in full
Type 1 — PP-1 · MAT3-007 · easy · drawing table_pp_l01
Stem: Look at Rocco's table of four objects tested in water. Which object floated?
- a) the tennis ball ← key
- b) the shell
- c) the egg
- d) the pebble
Why: Rocco's table has one row for each object. / The tennis ball's row says floats. / The shell, the egg and the pebble say sinks. / So the tennis ball floated.
Type 2 — PP-2 · MAT3-008 · easy
Stem: A magnet comes close to each of these objects. Which one does the magnet pull?
- a) a glass jar
- b) a cotton sock
- c) a plastic ruler
- d) a steel washer ← key
Why: A magnet pulls steel. / It does not pull glass, cotton or plastic. / So the magnet pulls the steel washer.
Type 4 — PP-3 · MAT3-060 · easy · drawing table_pp_concrete
Stem: Look at Tuva's table of three blocks tested the same way. Which block stayed whole?
- a) cement only
- b) gravel only
- c) cement and gravel ← key
- d) sand only
Why: Tuva's table has one row for each block. / The cement-and-gravel row says stayed whole. / Cement alone cracked, gravel alone rolled apart, and sand alone fell to bits. / So the cement-and-gravel block stayed whole.
Type 3 — PP-4 · MAT3-008 · medium · drawing sort_pp_wrong_one
Stem: Clem sorted these objects into the two groups. Which object is in the wrong group?
- a) the steel washer
- b) the steel spring ← key
- c) the cork
- d) the glass marble
Why: The steel spring sits in the group the magnet does not pull. / A magnet pulls steel. / So the steel spring is in the wrong group.
Medium because: the sort is judged against the rule, object by object, and the one that breaks it is found.
Type 5 — PP-5 · MAT3-060 + FOR3-007 · medium
Stem: Iker tests three lumps of papier-mâché to see which mix dries hardest. Which one thing should be different between the lumps?
- a) how big they are
- b) how long they dry
- c) what they are made of ← key
- d) how hard he presses
Why: Iker wants to know which mix dries hardest. / So what the lumps are made of is the one thing that changes. / Size, drying time and the push stay the same: a fair test.
Medium because: the fair test's rule is applied to a fresh question (which mix dries hardest) to pick the one variable.
Type 6 — PP-6 · MAT3-008 + MAT3-061 · medium · drawing table_pp_board
Stem: Dilan tested four materials for a notice board that magnets must hold papers to. Which material suits the board?
- a) cork
- b) plastic
- c) aluminum
- d) steel ← key
Why: The board needs a material a magnet pulls. / Dilan's table says the magnet pulls steel and not cork, plastic or aluminum. / So steel suits the board.
Medium because: a test result (the table) is turned into a choice for a job — two atoms, one read each.
Type 7 — PP-7 · MAT3-061 · medium
Stem: Rubber suits the handle grips of a bike. Which property makes it suit?
- a) Rubber is see-through.
- b) Rubber is grippy. ← key
- c) Rubber is soft.
- d) Rubber is shiny.
Why: Handle grips need to grip your hands. / Rubber is grippy. / So being grippy is the property that makes rubber suit the grips.
Medium because: the verdict is given and the reason is picked — the job's need has to be supplied by the student (grips grip).
Type 8 — PP-8 · MAT3-007 + MAT3-061 · hard · text entry · drawing table_pp_toy
Stem: Aisha wants a toy sailboat for the pond that floats. She tested four materials in water. Type the name of the material that suits the sailboat.
Accept: term_accept("wood") — wood · a wood · the wood · its wood · it is wood · it's wood · being wood
Why: A toy sailboat needs a material that floats. / Aisha's table says wood floats. / Steel, stone and glass sink. / So wood suits the sailboat.
Type 9 — PP-9 · MAT3-061 · hard · text entry
Stem: Aisha picks glass for the walls of a greenhouse, so that light gets to the plants. Type the property of glass that suits the job.
Accept: term_accept("see-through") + term_accept("clear") — see-through, see through, seethrough and clear, each bare and with a / the / its / it is / it's / being
Why: The greenhouse walls need to let light through. / Glass is see-through. / So being see-through is the property that suits the job.
Type 10 — PP-10 · MAT3-007 · hard · text entry · drawing tank_pp_raisin_lid
Stem: A raisin and a plastic lid were let go in two tanks of water. Look at the tanks. Type the name of the object that floats.
Accept: term_accept("plastic lid") + term_accept("lid") — plastic lid and lid, each bare and with a / the / its / it is / it's / being
Why: The raisin is on the bottom of its tank, so it sinks. / The plastic lid stays at the top of the water. / If it stays at the top, it floats. / So the plastic lid floats.