Skill: course-build → write-mcqs → write-explanation, design-check-sequence @ 264fe96 · re-instanced after the non-author review (REVIEW_G3T20_2026-09-28.md, B1, B5, F5–F7), 28 Sep 2026, night
Topic 20 — Solids, liquids and gases — the PP100's eight 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/G3T20.py (PP100, flagged TYPE_SHEET_ONLY). Eight types for eight atoms (the first sheet had ten; the reviewer's merge of the two breeze types and the fold of the water-in-a-jar type into the sort are applied). Type 6 (the sort by what the sample does) covers three atoms alone and is shown in three forms, so the sheet carries ten exemplars. If the topic splits after L04 (build record, decision 1), the sheet splits with it: types 1–5 to "Air is something", 6–8 to "Solids, liquids and gases". Once the types stand, about fifty items are generated from them, varying the scene KIND, the objects and the names, easy-heavy.
Every exemplar is a fresh instance. The reviewer found nine of the first twelve exemplars were lesson or practice items with the nouns changed. Every exemplar below sits on a scene KIND no quiz, practice item or taught example uses; the design-move inventory at the foot lists every item in the topic with its move and its scene so the claim can be checked, and the bank will be held to the same table.
James's rulings applied. Hard items are typed, never MCQs (28 Sep night): one text-entry type (the kind of matter, read off a drawn heap — the stem withholds the deciding words, review B5). Easy and medium are four-option MCQs. 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 chip that names the key; no stem of three or more sentences sits on an easy or medium item. "You cannot tell from this." is the fourth option on the sort type, and L08 now teaches the case it rests on (stuff shut in a box you cannot see into; review F5).
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 fact or one sort read off a described case; medium = the reason for an observation, or two ideas chained; hard = the kind produced (typed) on a drawn trap with the deciding words withheld.
The eight types
| Type | Items | Atom | Tag | Form | The stem asks… | The options / the accept | Exemplar scene |
|---|---|---|---|---|---|---|---|
| 1 | PP-1 | MAT3-063 + MAT3-064 | easy | MCQ | someone feels something they cannot see (moving air): what reaches them | countless tiny pieces of air / one big piece of air / drops of rain / nothing (a bank item may use air / light / water / nothing for the 063-only form) | Enya's hand out of a car window |
| 2 | PP-2 | MAT3-065 + MAT3-064 (pair) | easy | MCQ | which of two named things is made of tiny pieces far too small to see | only the solid thing / only the air / both / neither | a bicycle and the air in its tires |
| 3 | PP-7 | MAT3-065 | medium | MCQ | you can see X easily: why | four reasons: packed very close together / big enough to see / not made of pieces / one big piece | Lowri's red scarf |
| 4 | PP-3 | MAT3-022 | easy | MCQ, drawn | a container pushed open-end-down under water; inside it the water comes up only a little way: what keeps the water out | the container's glass / the outer vessel / nothing keeps it out / the air in the container | a bottle neck-down in a bucket |
| 5 | PP-8 | MAT3-022 + Topic 18's MAT3-062 (pair) | medium | MCQ | the container is turned right over and all the air comes out: what happens to the water inside | four happenings: stays low / goes out with the bubbles / fills the glass where the air was / turns into bubbles | Iolo's glass turned right over |
| 6 | PP-4 (gas), PP-5 (liquid), PP-6 (solid) | MAT3-023, MAT3-021, MAT3-020 | easy | MCQ | a described sample (what it does in its container): which kind of matter is it | a solid / a liquid / a gas / You cannot tell from this. | stuff pumped into a bounce house; paint in a tray; a toy car in a bathtub |
| 7 | PP-9 | MAT3-024 + MAT3-020 (pair) | medium | MCQ | a soft thing squashes: which tells you it is a solid | four features, all one line long: you can squash it flat / it goes back to its own shape / it feels soft / it takes up space on the chair | a cushion |
| 8 | PP-10 | MAT3-024 | hard | text, drawn | a drawn heap of small things poured into a jar, no sorting words in the stem: type the kind of matter — solid, liquid or gas | solid / a solid / the solid / solids (generated by kind_accept) | lentils in a jar |
Hard because (type 8): the stem withholds the deciding feature. The student reads the heap and the separate lentils off the drawing, decides that a thing that pours is still a solid because each piece keeps its own shape, and produces the word. In the bank type 8 supplies about twelve items on fresh drawn cases (flour, sugar, gravel, marbles, dried peas, a squashed cushion springing back, fog over a pond, a sealed box…), so the hard tier is all typed. Type 6's "cannot tell" is the key on one bank item per state (stuff shut in a box) and a distractor elsewhere.
Coverage (every atom alone, and the pairs)
| Atom | Types testing it alone | Pair types |
|---|---|---|
| MAT3-063 air is something | 1 (the air / light / water / nothing form) | 1 (the tiny-pieces form, with 064) |
| MAT3-064 air is tiny pieces | 1 (the tiny-pieces form) | 2 (with MAT3-065) |
| MAT3-065 everything is tiny pieces | 3 | 2 (with MAT3-064) |
| MAT3-022 air takes up space | 4 | 5 (with Topic 18's MAT3-062) |
| MAT3-023 gases spread out | 6 (gas form) | — |
| MAT3-021 liquids take the shape | 6 (liquid form; the flat top is the stem's behaviour) | — |
| MAT3-020 solids keep their shape | 6 (solid form) | 7 (with MAT3-024) |
| MAT3-024 sort the sample | 8 | 7 (with MAT3-020) |
At most two alone-types per atom. Order in the file: easy PP-1…PP-6 → medium PP-7…PP-9 → hard PP-10. Keys of the nine MCQs, in file order: A C D C B A A C B (A 3, B 2, C 3, D 1). Typed items: 1 of 10 on the sheet; in a bank of about fifty, type 8 supplies the whole hard tier.
Fresh instances — the design-move inventory
Every item in the topic, one line each: its design move (what the student does with what) and its scene. Two items may share a move only when their scene KIND differs; no exemplar shares a scene kind with any quiz, practice or taught case. The taught cases (the lessons' own scenes) are listed first, because a bank item on a taught scene is not fresh either.
| Item | Move | Scene |
|---|---|---|
| L01 taught | the fact shown | Astrid fans her face; Cormac on a windy hill (hair, flag); Tamsin breathes in |
| L02 taught | the fact shown | the same three scenes; the dots box; the cheek |
| L03 taught | the fact shown | a book, a wall, a glass of water, a balloon; one ant / hundreds of ants; one grain / a beach |
| L04 taught | the two demonstrations | Pim's cup with the paper towel in a bowl; the cup tipped right over; Ike's balloon (blown, tied, untied) |
| L05 taught | the example run | Huw's long and round balloons; a bike tire; a room; water in the long balloon |
| L06 taught | the example run | Winnie's juice in a glass, a bowl, a box; water in a jar; honey; milk; a spoon in the glass |
| L07 taught | the example run | Cormac's spoon in a glass, a bowl, a box; a block; a marble; a teddy bear; milk in the box |
| L08 taught | the awkward cases | Tamsin's sand; rice; a sponge; fog; a shut box |
| L01-01 | name the invisible stuff (what is it / what reaches / what takes up the space) | A boy runs fast down a path. He feels something moving past his face. … |
| L01-02 | judge a named child's claim (bare yes / no) | Lotta says a breeze is nothing at all, because she cannot see it. Is L… |
| L01-03 | name the invisible stuff (what is it / what reaches / what takes up the space) | A flag on a pole moves in the wind. What moves the flag? |
| L01-04 | yes / no on a described case | A girl breathes in. Her chest gets bigger. Did something go into her c… |
| L01-05 | yes / no on a described case | A boy holds his hand in front of an electric fan that is switched on. … |
| L01-06 | yes / no on a described case | Can you see the air in a room? |
| L01-07 | name the invisible stuff (what is it / what reaches / what takes up the space) | Dayo waves a book near a candle flame. The flame bends over. What made… |
| L01-08 | judge a named child's claim (bare yes / no) | Kaito says you can feel air even though you cannot see it. Is Kaito ri… |
| L01-V-01 | name the invisible stuff (what is it / what reaches / what takes up the space) | A girl waves a paper fan at her face. She feels a breeze. What reaches… |
| L02-01 | yes / no on a described case | Can you see one tiny piece of air? |
| L02-02 | judge a named child's claim (bare yes / no) | Mei says air is made of nothing. Is Mei right? |
| L02-03 | name the invisible stuff (what is it / what reaches / what takes up the space) | A breeze reaches Kemi's arm. What reaches her skin? |
| L02-04 | yes / no on a described case | Is air made of tiny pieces? |
| L02-05 | pick the reason / the deciding feature | Why can't you see the pieces that air is made of? |
| L02-06 | yes / no on a described case | Rin sits in a quiet room with the windows shut. Are tiny pieces of air… |
| L02-07 | judge a named child's claim (bare yes / no) | Alfie says you can see the pieces of air if you look very closely. Is … |
| L02-08 | name the invisible stuff (what is it / what reaches / what takes up the space) | Elis breathes in. What goes in through his nose? |
| L02-09 | type the term from its meaning | Scientists have a word for the tiny pieces that air is made of. The wo… |
| L02-V-01 | name the invisible stuff (what is it / what reaches / what takes up the space) | This drawing shows the air in a jar, as if you could see it. What is a… |
| L03-01 | yes / no on a described case | Is a brick made of tiny pieces far too small to see? |
| L03-02 | yes / no on a described case | Is the water in a swimming pool made of tiny pieces far too small to s… |
| L03-03 | judge a named child's claim (bare yes / no) | Seren says only air is made of tiny pieces, and a rock is just one big… |
| L03-04 | pick the reason / the deciding feature | You can see a wall easily. Why can you see the wall? |
| L03-05 | yes / no on a described case | Can you see one tiny piece of a rock on its own? |
| L03-06 | yes / no on a described case | Is your own hand made of tiny pieces far too small to see? |
| L03-07 | judge a named child's claim (bare yes / no) | Neel says the tiny pieces of a table are big enough to see if you look… |
| L03-08 | type the term from its meaning | Stuff of every kind, like a book, water and the air, is called ___. |
| L03-V-01 | yes / no on a described case | Here is a metal spoon. Is the spoon made of tiny pieces far too small … |
| L04-01 | yes / no on a described case | A shoe fills the space inside a shoebox. Can a ball be in that same sp… |
| L04-02 | name the invisible stuff (what is it / what reaches / what takes up the space) | Zeph pushes an upside-down glass with a dry sock inside under the wate… |
| L04-03 | name the invisible stuff (what is it / what reaches / what takes up the space) | Maja blows air into a balloon and ties it. The balloon stays big. What… |
| L04-04 | judge a named child's claim (bare yes / no) | Zoya says a tied balloon has nothing inside it. Is Zoya right? |
| L04-05 | predict the happening | Leif unties a big balloon. The air comes out. What happens to the ball… |
| L04-06 | yes / no on a described case | Does air take up space? |
| L04-07 | pick the reason / the deciding feature | Femke tips an upside-down glass under the water. A bubble comes out. W… |
| L04-08 | name the invisible stuff (what is it / what reaches / what takes up the space) | Teun pumps air into a flat bike tire. The tire gets fat and firm. What… |
| L04-09 | judge a named child's claim (bare yes / no) | Riku says an open bottle that looks empty is really full of air. Is Ri… |
| L04-10 | name the invisible stuff (what is it / what reaches / what takes up the space) | Which of these takes up space? |
| L04-V-01 | name the invisible stuff (what is it / what reaches / what takes up the space) | An upside-down jar with a dry cotton ball inside is pushed under the w… |
| L05-01 | yes / no on a described case | Air is pumped into a square box. It spreads out to fill every corner. … |
| L05-02 | yes / no on a described case | Siri pours milk into a jar. The milk sits at the bottom with a flat to… |
| L05-03 | pick which happening the kind does / which thing is the kind | Which does a gas do? |
| L05-04 | predict the happening | The gas from a soda's bubbles is let into a big jar with a lid. Where … |
| L05-05 | judge a named child's claim (bare yes / no) | Diya says air has a shape of its own, like a ball. Is Diya right? |
| L05-06 | yes / no on a described case | Jip blows air into a balloon shaped like a dog. The air goes into the … |
| L05-07 | judge a named child's claim (bare yes / no) | Barney says a gas let into a big box will spread out to fill the whole… |
| L05-08 | yes / no on a described case | Wyn pours sand into a jar. The sand makes a heap at the bottom. Does t… |
| L05-09 | pick which happening the kind does / which thing is the kind | Which of these is a gas? |
| L05-10 | type the term from its meaning | A kind of matter that spreads out to fill all the space it is given is… |
| L05-V-01 | predict the happening | Ylva pumps air into a flat pool ring. Where does the air go? |
| L06-01 | yes / no on a described case | Ciara pours cooking oil into a pan. The oil takes the shape of the pan… |
| L06-02 | yes / no on a described case | Syrup pours very slowly into a bowl and takes the bowl's shape. Is syr… |
| L06-03 | yes / no on a described case | A pencil is put into a cup. It stays pencil-shaped. Is a pencil a liqu… |
| L06-04 | judge a named child's claim (bare yes / no) | Ife says water has a shape of its own: a puddle shape. Is Ife right? |
| L06-05 | pick which happening the kind does / which thing is the kind | Which does a liquid do? |
| L06-06 | predict the happening | Eoin pours vinegar into a tall bottle. Where is the top of the vinegar… |
| L06-07 | yes / no on a described case | Melted butter pours into a pan and takes the pan's shape. Is melted bu… |
| L06-08 | yes / no on a described case | The air in a bottle spreads out to fill the whole bottle. Is air a liq… |
| L06-09 | judge a named child's claim (bare yes / no) | Monty says honey is not a liquid, because it pours so slowly. Is Monty… |
| L06-10 | type the term from its meaning | A kind of matter that pours and takes the shape of whatever holds it i… |
| L06-V-01 | name the invisible stuff (what is it / what reaches / what takes up the space) | Nancy pours the same milk into a tall pitcher and a wide bowl. What sh… |
| L07-01 | yes / no on a described case | A wooden block is put in a bag, then on a shelf. It stays block-shaped… |
| L07-02 | yes / no on a described case | Carys pours water into a bag. The water takes the shape of the bag. Is… |
| L07-03 | pick which happening the kind does / which thing is the kind | Which does a solid do? |
| L07-04 | judge a named child's claim (bare yes / no) | Yui says a soft pillow is not a solid, because you can squash it. Is Y… |
| L07-05 | yes / no on a described case | A rubber eraser is moved from a pencil case to a desk. It stays eraser… |
| L07-06 | sort a described sample on the fixed set | A coin is dropped into a bowl. It stays coin-shaped. Which kind of mat… |
| L07-07 | judge a named child's claim (bare yes / no) | Tara says there are three kinds of matter: gas, liquid and solid. Is T… |
| L07-08 | yes / no on a described case | The air in a box spreads out to fill the whole box. Is air a solid? |
| L07-09 | sort a described sample on the fixed set | Oil poured into a cup takes the shape of the cup. Which kind of matter… |
| L07-10 | type the term from its meaning | A kind of matter that keeps its own shape wherever you put it is calle… |
| L07-V-01 | name the invisible stuff (what is it / what reaches / what takes up the space) | A metal key is put into a cup, then into a bowl. What shape is the key… |
| L08-01 | sort a described sample on the fixed set | Sugar pours from a jar into a bowl and makes a heap. Each grain keeps … |
| L08-02 | sort a described sample on the fixed set | Honey pours slowly into a cup and takes the cup's shape, with a flat t… |
| L08-03 | sort a described sample on the fixed set | Air pumped into a ball spreads out to fill the whole ball. Which kind … |
| L08-04 | judge a named child's claim (bare yes / no) | Kabir says sand is a liquid, because it pours. Is Kabir right? |
| L08-05 | sort a described sample on the fixed set | A bath sponge is squashed flat, then let go. It goes back to its own s… |
| L08-06 | sort a described sample on the fixed set | Ozzie squeezes glue into a cup. The glue flows slowly and takes the cu… |
| L08-07 | sort a described sample on the fixed set | Cream is poured from a carton into a pitcher. It takes the pitcher's s… |
| L08-08 | name the invisible stuff (what is it / what reaches / what takes up the space) | Fog covers a field. What is fog made of? |
| L08-09 | sort a described sample on the fixed set | The stuff from the bubbles in a soda is let into a jar. It spreads out… |
| L08-10 | judge a named child's claim (bare yes / no) | Emi says a sponge is a liquid, because you can squash it. Is Emi right… |
| L08-11 | pick the reason / the deciding feature | Rice pours like water, but rice is a solid. Which tells you that rice … |
| L08-12 | sort a described sample on the fixed set | Milk poured into a glass has a flat top and takes the glass's shape. W… |
| L08-13 | sort a described sample on the fixed set (+ cannot tell) | Some stuff is shut inside a closed box. Nobody has seen what it does. … |
| L08-V-01 | sort a described sample on the fixed set | Rice pours from a bag into a bowl. Each grain keeps its own shape. Whi… |
| SUMMARY-01 | name the invisible stuff (what is it / what reaches / what takes up the space) | Lieke feels the wind on her face at the beach. What is the wind? |
| SUMMARY-02 | sort a described sample on the fixed set | The air is let out of a bike tire in a room. It spreads out into the w… |
| SUMMARY-03 | name the invisible stuff (what is it / what reaches / what takes up the space) | An upside-down cup with a dry tissue inside is pushed under the water.… |
| PR-01 | name the invisible stuff (what is it / what reaches / what takes up the space) | On a hot bus, a small fan blows at the back of a girl's neck. She feel… |
| PR-02 | yes / no on a described case | Is the air inside a closed cupboard made of tiny pieces far too small … |
| PR-03 | which of two named things is made of tiny pieces (both) | Which is made of tiny pieces far too small to see? |
| PR-04 | name the invisible stuff (what is it / what reaches / what takes up the space) | A boy holds his thumb tight over the top of a drinking straw and pushe… |
| PR-05 | pick which happening the kind does / which thing is the kind | A camping mattress is pumped up until it is fat and firm. Which does t… |
| PR-06 | sort a described sample on the fixed set | Molasses runs very slowly across a plate and settles with a flat top. … |
| PR-07 | sort a described sample on the fixed set | A brick is moved from a wall to a wheelbarrow. It stays brick-shaped. … |
| PR-08 | yes / no on a described case | Salt pours from a shaker onto a plate and makes a little heap. Is salt… |
| PR-09 | judge a named child's claim (bare yes / no) | Sora says the air in a balloon has no tiny pieces in it, because she c… |
| PR-10 | name the invisible stuff (what is it / what reaches / what takes up the space) | A brick is matter. Which is true of the brick? |
| PR-11 | predict the happening | A pool float is left with its plug open. Slowly, the air comes out. Wh… |
| PR-12 | written answer: what is inside and how you know | Tunde says a pumped-up bike tire has nothing inside it. Say what is in… |
| PR-13 | type the term from its meaning | Stuff of every kind, like a book, water and the air, is called ___. |
| PR-14 | type the term from its meaning | A kind of matter that spreads out to fill all the space it is given is… |
| PR-15 | type the term from its meaning | A kind of matter that pours and takes the shape of whatever holds it i… |
| PR-16 | type the term from its meaning | A kind of matter that keeps its own shape wherever you put it is calle… |
| PP-01 | name the invisible stuff (what is it / what reaches / what takes up the space) | Enya holds her hand out of the window of a fast car, and something she… |
| PP-02 | which of two named things is made of tiny pieces (both) | Think of a bicycle and the air in its tires. Which is made of tiny pie… |
| PP-03 | name the invisible stuff (what is it / what reaches / what takes up the space) | An open bottle is pushed neck-down into a bucket of water, and inside … |
| PP-04 | sort a described sample on the fixed set (+ cannot tell) | The stuff pumped into a bounce house spreads out to fill every part of… |
| PP-05 | sort a described sample on the fixed set (+ cannot tell) | Paint poured into a tray takes the tray's shape, with a flat top. Whic… |
| PP-06 | sort a described sample on the fixed set (+ cannot tell) | A toy car dropped into a bathtub stays car-shaped. Which kind of matte… |
| PP-07 | pick the reason / the deciding feature | Lowri can see her red scarf easily. Why can she see the scarf? |
| PP-08 | predict the happening | Iolo turns an upside-down glass right over under the water, and all th… |
| PP-09 | pick the reason / the deciding feature | A cushion squashes when you sit on it. Which tells you that the cushio… |
| PP-10 | type the kind of matter from a drawn heap (the deciding feature withheld) | Lentils were poured from a bag into this jar. Type the kind of matter … |
Reading the table: the ten exemplars' scenes (a hand out of a car window; a bicycle's tires; a scarf; a bottle in a bucket; a glass turned right over; a bounce house; a paint tray; a toy car in a bathtub; a cushion; lentils in a jar) appear in no other row. The practice set's scenes (a bus fan; a cupboard; a fish tank; a drinking straw; a camping mattress; molasses on a plate; a brick in a wheelbarrow; salt from a shaker; a balloon's pieces; a brick's pieces; a pool float's plug; a bike tire's inside) appear in no quiz. The two practice items that share a move with a quiz item (PR-7 with L07-06, the solid sort; PR-3 with the bank's type 2) differ in scene kind (a wheelbarrow against a bowl; a fish tank against a bicycle).
The exemplars, in full
Type 1 — PP-1 · MAT3-063 + MAT3-064 · easy
Stem: Enya holds her hand out of the window of a fast car, and something she cannot see reaches her hand. What reaches it?
- a) countless tiny pieces of air ← key
- b) one big piece of air
- c) drops of rain
- d) nothing
Why: The car moves through the air. / The air moves past Enya's hand. / Air is made of tiny pieces far too small to see. / So countless tiny pieces of air reach her hand.
Type 2 — PP-2 · MAT3-065 + MAT3-064 · easy
Stem: Think of a bicycle and the air in its tires. Which is made of tiny pieces far too small to see?
- a) only the bicycle
- b) only the air in its tires
- c) both the bicycle and the air in its tires ← key
- d) neither of them
Why: The bicycle is matter, and the air in its tires is matter. / Every kind of matter is made of tiny pieces far too small to see. / So both are.
Type 4 — PP-3 · MAT3-022 · easy · drawing bottle_bucket_pp_svg
Stem: An open bottle is pushed neck-down into a bucket of water, and inside it the water comes up only a little way. What keeps the water out of the rest of the bottle?
- a) the bottle's glass
- b) the bucket
- c) nothing keeps it out
- d) the air in the bottle ← key
Why: The bottle was full of air. / The air takes up the space inside the bottle. / Nothing else can be in that space at the same time. / So the air keeps the water out of the rest of the bottle.
Type 6, gas form — PP-4 · MAT3-023 · easy
Stem: The stuff pumped into a bounce house spreads out to fill every part of it. Which kind of matter is it?
- a) a solid
- b) a liquid
- c) a gas ← key
- d) You cannot tell from this.
Why: The stuff spreads out to fill every part of the bounce house. / A gas spreads out to fill all the space it is given. / So it is a gas.
Type 6, liquid form — PP-5 · MAT3-021 · easy
Stem: Paint poured into a tray takes the tray's shape, with a flat top. Which kind of matter is the paint?
- a) a solid
- b) a liquid ← key
- c) a gas
- d) You cannot tell from this.
Why: The paint pours. / It takes the shape of the tray, with a flat top. / A liquid pours and takes its container's shape. / So the paint is a liquid.
Type 6, solid form — PP-6 · MAT3-020 · easy
Stem: A toy car dropped into a bathtub stays car-shaped. Which kind of matter is the toy car?
- a) a solid ← key
- b) a liquid
- c) a gas
- d) You cannot tell from this.
Why: The toy car stays car-shaped in the bathtub. / A solid keeps its own shape wherever you put it. / So the toy car is a solid.
Type 3 — PP-7 · MAT3-065 · medium
Stem: Lowri can see her red scarf easily. Why can she see the scarf?
- a) The scarf's pieces are packed very close together. ← key
- b) The scarf's pieces are big enough to see.
- c) The scarf is not made of pieces.
- d) The scarf is one big piece, not tiny pieces.
Why: The scarf is matter, so it is made of tiny pieces far too small to see. / Its pieces are packed very close together. / Countless pieces packed close together are easy to see. / So Lowri can see the scarf.
Type 5 — PP-8 · MAT3-022 + MAT3-062 · medium
Stem: Iolo turns an upside-down glass right over under the water, and all the air comes out in bubbles. What happens to the water inside the glass?
- a) It stays low in the glass.
- b) It goes out with the bubbles.
- c) It fills the glass, where the air was. ← key
- d) It turns into bubbles too.
Why: The bubbles are the air coming out of the glass. / The air no longer takes up the space inside. / Water goes in where the air was. / So the water fills the glass.
Type 7 — PP-9 · MAT3-024 + MAT3-020 · medium
Stem: A cushion squashes when you sit on it. Which tells you that the cushion is a solid?
- a) You can squash it flat with one hand.
- b) It goes back to its own shape. ← key
- c) It feels soft when you sit on it.
- d) It takes up space on the chair.
Why: You can squash a cushion, and it is soft, but neither sorts it. / Everything takes up space. / When you get up, the cushion goes back to its own shape, and a solid keeps its own shape. / So that is what tells you the cushion is a solid.
Type 8 — PP-10 · MAT3-024 · hard · text entry · drawing lentils_jar_svg
Stem: Lentils were poured from a bag into this jar. Type the kind of matter the lentils are: solid, liquid or gas.
Accept (generated by kind_accept("solid")): solid · a solid · the solid · solids
Why: The lentils poured, so they look like a liquid. / But they make a heap, not a flat top, and each lentil keeps its own shape. / A solid keeps its own shape. / So the lentils are solids: many small solids.
Hard because: the stem withholds the deciding feature; the drawing (a heap with a pointed top, single lentils separate from each other) is what the student must read, and the word is produced, not recognised. The stem lists the three words because a grade 3 child otherwise types "lentils" or "food" (build record, decision 4 — the reviewer's call: yes, the listing is fine because the difficulty is in the case).