Skill: course-build → write-mcqs → write-explanation, design-check-sequence @ 58d971a
Topic 18 — Which has more? — the PP100's nine 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/G3T18.py (PP100, flagged TYPE_SHEET_ONLY). Nine types for four atoms; three types carry a second form, so the sheet has twelve exemplars: type 1 on the pan balance and on two of Topic 17's digital scales; types 5 and 7 each with the instance where the setup rule fails and "You cannot tell" is the key. No other bank item exists yet. Once the types stand, about fifty items are generated from them, varying the objects, the levels and the names, easy-heavy.
Revised 28 Sep 2026 (night) after the non-author review (REVIEW_G3T18_2026-09-28.md): PP-6 re-instanced on a fresh scene and name (B3); PP-7 re-instanced (F9); PP-11's balance result moved onto the drawing as a chip so the stem prints no answer, and its ball drawn as a solid rubber ball (F5, F6); the "cannot tell" fourth option is now KEYED once on the cylinder type (a floating cork) and once on the thermometer type (two readings from different sides) — on the balance type it is never keyed, and blueprint decision 4 asks James whether it stays (F8); every "cannot be compared" line reworded (F2); the grid drawing fills its square edge to edge (B1).
James's rulings applied. Hard items are typed, never MCQs (28 Sep night): two text-entry types (the name of the object) and one numeric-entry type (the warmer reading, with its unit). Easy and medium are four-option MCQs. Every comparison is drawn (a balance, two cylinders, two thermometers) except the two "different sides" items, whose point is that two prose numbers from different sides decide nothing; 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 drawn level is one the imported scale gives (figures.py asserts it); every object in a cylinder sinks, except the one floating cork whose item keys "cannot tell".
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 comparison read off one drawing; medium = the fact applied to a fresh case, the rule that fixes a wrong move, or a case where the setup rule fails; hard = the name or the number produced (typed) on the trap instance, or two ideas held apart.
The nine types
| Type | Items | Atom | Tag | Form | The stem asks… | The options / the accept | Exemplar scenes |
|---|---|---|---|---|---|---|---|
| 1 | PP-1 (balance), PP-2 (scales) | MAT3-004 (PP-2 pairs it with Topic 17's SR3-004) | easy | MCQ, drawn | which of the two objects has more mass | the X / the Y / They have the same mass. / You cannot tell from the balance (scales). | a sneaker and a sock on a balance; a book and an eraser on two digital scales (480 g, 30 g) |
| 2 | PP-10 | MAT3-004 | hard | text, drawn | type the name of the object with more mass, on a balance where the much bigger object's pan hangs higher | marble / the marble / a marble | a blown-up balloon and a marble |
| 3 | PP-3 | MAT3-062 | easy | MCQ, drawn | one square of the grid is filled: which squares can a second thing go on | D only / none of them / A, B or C / A, B, C or D | a sneaker filling square D |
| 4 | PP-6 | MAT3-062 + MAT3-005 (pair) | medium | MCQ | a sinking object goes into water: what does the water do | four happenings: moves down / moves up / stays / soaks into the potato | Rafe's potato in a pan |
| 5 | PP-4; PP-8 (second form) | MAT3-005 | easy; medium | MCQ, drawn | two cylinders that started at 50 mL, an object in each: which takes up more space; second form: one object floats | the X / the Y / They take up the same space. / You cannot tell from the water. | a shell (72 mL) and a small stone (58 mL); a glass bead (58) and a FLOATING cork — key "cannot tell" |
| 6 | PP-11 | MAT3-005 + MAT3-004 (pair) | hard | text, drawn | the drawing's chip says the balance found the spoon has more mass; the cylinders are drawn: type the name of the object that takes up more space | rubber ball / the rubber ball / a rubber ball / ball / the ball / a ball | a spoon (54 mL, more mass) and a solid rubber ball (74 mL) |
| 7 | PP-5; PP-9 (second form) | MAT3-006 | easy; medium | MCQ, drawn; second form in prose | two thermometers, Fahrenheit side: which is warmer; second form: two readings from different sides | the X / the Y / They are the same temperature. / You cannot tell from the thermometers (these two numbers). | the sand (98 °F) and the sea (72 °F); cup A 10 on the Celsius side, cup B 40 on the Fahrenheit side — key "cannot tell" |
| 8 | PP-7 | MAT3-006 | medium | MCQ | one reading from the Celsius side, one from the Fahrenheit side: what should she do to find the warmer one | four moves: pick the bigger / add them / read the same side on both / pick the smaller | Marlo's cocoa (15 on the Celsius side) and milk (50 on the Fahrenheit side) |
| 9 | PP-12 | MAT3-006 + Topic 17's SR3-023 (pair) | hard | numeric, drawn | two thermometers: find the warmer one, read it, type the number of degrees Fahrenheit | acc(84, "F"): 84 and the unit in a child's forms | a mug (84 °F) and a glass (46 °F) |
Hard because (type 2): the name is produced, not recognised, on the instance that invites the wrong answer — the balloon is many times the marble's size and its pan hangs higher. Hard because (type 6): two ideas are held apart (the balance decided mass; the water decides space; the object with more mass takes up LESS space here) and the name is typed. Hard because (type 9): compare the two liquid tops, choose the warmer, then perform Topic 17's reading routine on that card and type the number with its unit. Medium because (types 5 and 7, second forms): the student must notice that the setup rule has failed — the object floats; the two numbers come from different sides — before answering, and "cannot tell" is the honest answer, never padding.
Coverage (every atom alone, and the pairs)
| Atom | Types testing it alone | Pair types |
|---|---|---|
| MAT3-004 which has more mass | 1, 2 | 1 second form (with Topic 17's SR3-004: two digital scales); 6 (with MAT3-005) |
| MAT3-062 everything takes up space | 3 | 4 (with MAT3-005: the water moves up because the potato takes up space) |
| MAT3-005 which takes up more space | 5 (both forms) | 4 (with MAT3-062); 6 (with MAT3-004) |
| MAT3-006 which is warmer | 7 (both forms), 8 | 9 (with Topic 17's SR3-023: read the warmer one) |
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-5 → medium PP-6…PP-9 → hard PP-10, PP-11, PP-12. Keys of the nine MCQs, in file order: PP-1 B · PP-2 A · PP-3 C · PP-4 A · PP-5 D · PP-6 B · PP-7 C · PP-8 C · PP-9 D (two of A and B, three of C, two of D). Typed items: 3 of 12 on the sheet; in a bank of about fifty, types 2, 6 and 9 supply 12–15 typed items on fresh objects and levels (every even mL level 52–98 above the 50 start; every even F level 22–108, less the levels the lessons and quizzes use), and the two "cannot tell" forms supply two or three items each.
Fresh instances
No exemplar reuses a lesson, quiz or practice scene: the sneaker and sock, the book and eraser on scales, the sneaker filling square D, the shell and small stone, the sand and sea, Rafe's potato in a pan, Marlo's cocoa and milk, the floating cork, cup A and cup B at 10 °C / 40 °F, the balloon and marble, the spoon and rubber ball, the mug and glass appear nowhere else in the topic. (The practice set's Dov drops a marble into a jar and Liv's 25 / 70 are the lesson-side instances of types 4 and 8; the exemplars now differ from them in scene kind — a potato in a pan; named drinks — not only in nouns. The summary's attached questions reuse three quiz figures, as attached questions may — they are lesson checks, not bank items.)
The exemplars, in full
Type 1 — PP-1 · MAT3-004 · easy · drawing bal_pp_shoe_sock
Stem: Look at the pan balance. Which has more mass?
- the sock
- the sneaker ← key
- They have the same mass.
- You cannot tell from the balance.
Why: The sneaker's pan hangs lower. / The pan that hangs lower holds the object with more mass. / So the sneaker has more mass.
Type 1, second form — PP-2 · MAT3-004 (+ SR3-004) · easy · drawing scales_pp_book_eraser
Stem: A book sits on one digital scale and an eraser on another. Which has more mass?
- the book ← key
- the eraser
- They have the same mass.
- You cannot tell from the scales.
Why: A digital scale measures mass in grams. / The book's scale reads 480 g and the eraser's reads 30 g. / 480 is the bigger number. / So the book has more mass.
Type 3 — PP-3 · MAT3-062 · easy · drawing grid_pp_shoe_D
Stem: A sneaker lies on square D. Which squares can a cup go on?
- D only
- none of them
- A, B or C ← key
- A, B, C or D
Why: The sneaker takes up space D. / Nothing else can be in space D at the same time. / Squares A, B and C are empty. / So the cup can go on A, B or C.
Type 5 — PP-4 · MAT3-005 · easy · drawing cyl_pp_shell_stone
Stem: Both cylinders had water at 50 mL before. Which takes up more space?
- the shell ← key
- the small stone
- They take up the same space.
- You cannot tell from the water.
Why: Both started at 50 mL. / The shell's water is higher than the stone's. / The water rises higher for the object that takes up more space. / So the shell takes up more space.
Type 7 — PP-5 · MAT3-006 · easy · drawing therm_pp_sand_sea
Stem: A thermometer stands in the sand and one in the sea. Which is warmer?
- the sea
- They are the same temperature.
- You cannot tell from the thermometers.
- the sand ← key
Why: Both thermometers are read on the Fahrenheit side. / The sand's reads 98 °F and the sea's reads 72 °F. / 98 is the bigger number. / So the sand is warmer.
Type 4 — PP-6 · MAT3-062 + MAT3-005 · medium
Stem: Rafe lowers a potato into a pan of water, and it sinks. What does the water do?
- The water moves down.
- The water moves up. ← key
- The water stays where it was.
- The water soaks into the potato.
Why: The potato takes up space in the pan. / The water cannot be in that space at the same time. / So the water moves up.
Medium because: the fact (L02) is applied to a fresh scene to predict a happening the student has not been told.
Type 8 — PP-7 · MAT3-006 · medium
Stem: Marlo reads 15 on the Celsius side of the cocoa's thermometer and 50 on the Fahrenheit side of the milk's. What should she do to find the warmer one?
- pick the bigger number
- add the two numbers
- read the same side on both ← key
- pick the smaller number
Why: The two numbers come from different sides. / So the bigger number does not tell her which is warmer. / Marlo reads the same side on both. / Then the bigger number is the warmer one.
Medium because: the rule that fixes a wrong move is picked, not a reading made; "pick the bigger number" is the register's trap (warmer = bigger number only if the same side is read).
Type 5, second form — PP-8 · MAT3-005 · medium · drawing cyl_pp_bead_cork_float
Stem: Both cylinders had water at 50 mL before, and the cork floats. Which takes up more space?
- the glass bead
- the cork
- You cannot tell from the water. ← key
- They take up the same space.
Why: The water shows an object's space only when the object sinks to the bottom. / The cork floats, so its water level does not show its space. / So the water cannot tell you which takes up more space.
Medium because: the setup rule ("each object sinks to the bottom") has failed, and the student must notice that before comparing; a student who compares the two tops anyway picks the bead.
Type 7, second form — PP-9 · MAT3-006 · medium
Stem: Cup A's thermometer reads 10 on the Celsius side, and cup B's reads 40 on the Fahrenheit side. Which cup is warmer?
- cup A
- cup B
- They are the same temperature.
- You cannot tell from these two numbers. ← key
Why: The two numbers come from different sides. / So the bigger number does not tell you which is warmer. / Read the same side on both first.
Medium because: the setup rule ("read the same side on both") has failed; "cup B" is the register's trap (the bigger number). No drawing, on purpose: a drawing with both sides would let the student read the same side and answer.
Type 2 — PP-10 · MAT3-004 · hard · text entry · drawing bal_pp_balloon_marble
Stem: Look at the pan balance. Type the name of the object with more mass.
Accept: marble · the marble · a marble
Why: The marble's pan hangs lower. / The pan that hangs lower holds the object with more mass. / So the marble has more mass, even though the balloon is much bigger.
Type 6 — PP-11 · MAT3-005 + MAT3-004 · hard · text entry · drawing cyl_pp_spoon_ball (a chip on the drawing reads THE BALANCE: THE SPOON HAS MORE MASS)
Stem: Both cylinders had water at 50 mL before. Type the name of the object that takes up more space.
Accept: rubber ball · the rubber ball · a rubber ball · ball · the ball · a ball
Why: The balance compares mass; the water compares space. / Both cylinders started at 50 mL. / The rubber ball's water is higher than the spoon's. / So the rubber ball takes up more space, even though the spoon has more mass.
Type 9 — PP-12 · MAT3-006 + SR3-023 · hard · numeric entry · drawing therm_pp_mug_glass
Stem: A thermometer stands in the mug and one in the glass. Read the warmer one. What does it read? Type the number of degrees Fahrenheit.
Accept: acc(84, "F") — 84, 84 °F, 84°F, 84° F, 84 F, 84 degrees, 84 degrees F, 84 degrees Fahrenheit, 84 Fahrenheit, 84 degree Fahrenheit
Why: The mug's liquid stands higher than the glass's, so the mug is warmer. / On the mug's thermometer, the number below the top is 80. / The top is two marks above 80: 82, 84. / So it reads 84 °F.