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Skill: course-build → write-mcqs → write-explanation, design-check-sequence @ efd8fba (v1); v2 reviews applied @ 80719f4, 2 Oct 2026 — the changed rows are marked v2; v3 polish @ fb37d14 (Lyla renamed Josie after Reader C read Luna and Lyla as one child; the map legend is now a strip along the bottom of every map, 13 px at phone width)

Topic 26 — How Earth's parts act on one another — the PP100's question types, with their exemplars

What this page is. James reads a bank as its question TYPES first (vault: A bank is reviewed as its question types first, one exemplar each). Under the Grade 4 standing brief the bank is built straight away (53 items in content/G4T26_pp100_bank.py); this sheet is the way in. v2 (2 Oct 2026): type 9 retagged easy (one decision); type 6's hot-wind-dries-a-pond pair replaced (evaporation was on the bar list); types 7, 9 and 10-hard re-scened where a lesson scene had been renamed; every key now one clause and never the longest by more than 12 characters and 25 % (check_key_tells.py: 0 of 108); type 12's options end at the reason; the typed accept lists take "map legend" and "a map key"; the four parts are declared in KEY_TELL_EXEMPT_SETS. Each type line says what the stem asks, what the options are, which atom and tier it serves, and gives one exemplar in full. Freshness: no bank item reuses a lesson, quiz, attached or practice scene (the re-performed scene-noun grep is in the build record).

Rulings already applied. Four options on every MCQ; the hard tier is typed where typing does a job ("legend", six letters, "key" accepted) and MCQ where the term is eleven letters ("interaction", RECALL_BY_MCQ); no option bundles a verdict with its reason — every claim is "X is wrong. What is the correct reason?" over four single-statement reasons; the acting part is always said first in every pair option ("the air acts on the land"); letters on drawn maps are J–R; a map item's blind text lists what is drawn where and never a reading; one atom per item; difficulty rises with the atom's position (EAR4-026 easy and medium plus its two typed term items; EAR4-080 easy to hard; EAR4-081 easy one-part reads, medium pairs, hard two-step and set items — v2).

The bar list (real things a generated item must never use): the sphere names (hydrosphere, geosphere, atmosphere, biosphere — grade 6-8's); "ecosystem", "environment", "habitat", "predator", "prey" (Grade 5 words); any figurative verb (a river "eats" or "carves", the wind "sculpts"); water-on-air events (evaporation, fog) as pair items — the direction is arguable for a nine-year-old and the lesson did not teach the pair; any event where both things are in ONE part offered as a key (a hawk and a mouse; a river into a lake); a non-US animal; the lesson scenes (the walk, Louis's map, the river bank, the lake in wind, roots on the hill, rain on the grass field, the pile of sand with grass, the beaver dam, the river mouth, the flooded field) and the quiz, attached and practice scenes listed at the top of the bank file.

The twelve types

TypeItemsAtomTierFormThe stem asks…The options / the acceptExemplar scenes
15026easyMCQwhat view a map shows; what the legend tells; what the N arrow shows; which thing is drawn blue; what a thin blue line isfour views / four jobs / four thingsa park map; a legend that says blue is water
24026easyMCQ, drawn map with letters J K L Mwhich letter marks the town / the sea / the lake / the forestthe four letters (from the same list that drew them)four fresh map layouts (pp_map_1 to 4)
34026mediumMCQ, drawn map (3) and a claim (1)where both towns sit; which way the river runs; what sits between the lake and the hills; Luna's "a map shows the hill from the side" — the correct reasonfour positions / four directions / four things / four reasonspp_map_5, 6, 7; Luna's claim
42026hardtypedthe name of the box that says what each color or shape stands forlegend, the legend, a legend, map legend, the map legend, a map legend, key, the key, a key, map key, the map key, a map key + child spellings (v2)a hiker's map; a state-park map with a star and a triangle
56080easyMCQwhich of four things is one of Earth's four big parts (the Sun, the Moon, the stars, the planets as the near misses); which part three named things belong tothe four parts / one part + three space thingsa pelican, a palm tree and a fisherman; a sandbar, a cliff and canyon walls; a breeze and a gust; a hailstone, a pond and a cloud
65080mediumMCQwhich of four events is one part of Earth acting on ANOTHER part (three within-one-part near misses each time)one cross-part event + three same-part events, every option the key's length and shape (v2)rocks crush bushes; wind blows spray off a waterfall (v2, was a hot wind dries a pond — evaporation is on the bar list); rain opens cactus flowers; ash kills hillside plants; an alligator digs the mud
74080hardMCQa child's claim is wrong (air is nothing; a stream and its rocky bed are separate; living things only live in a place; water never leaves the sea) — the correct reasonfour one-clause reasons (v2: keys were two clauses and the lesson's own scenes)Luna (waves), Louis (stones rolled along a stream bed), Josie (wild pigs dig a field), Luna
82080hardMCQ keyed on the termthe word for one part acting on another, from a fresh case; which sentence uses "interaction" correctlyan interaction / a legend / a pattern / a landslide; four sentencesfrost cracks a boulder; roots split a rock against a robin and a worm
96081easy (v2, was medium: one decision)MCQ, the four partswhich part is doing the acting / which part is being changedthe air / the land / the water / the living thingswind blows maple leaves off (v2, was a hurricane and palm trees — the quiz's leaning pines renamed); lava boils the sea; earthworms; bison roll a bare dip (v2, was moles — the quiz's prairie dogs renamed); mangrove roots; a cold wind and a pond
1011081medium (8), hard (3)MCQ, four pair optionswhich two parts act in the event; HARD: a two-step event, the asked step must be isolated"the X acts on the Y" × 4dandelion seeds; an earthquake and a lake; moss on a boulder; snowmelt and seeds; desert sand on a highway; water lilies; snowmelt grooves a road; rockfall dust; HARD: rain washes gravel → the gravel fills a pond (v2, was rain → soil slide blocks a stream, L03's transfer and L03-q4 stitched); wind → sea water kills grass; a cloud of ash, "ash is tiny pieces of rock" → the lake turns gray (v2: the acting material plainly one part)
112081hardmulti-selectselect the TWO parts that act on each otherthe four parts, two keyedgeese churn a still pond into waves (v2, was "the water turns muddy" — mud is land, a third part); lava burns a forest
122081hardMCQa child names the changed part first ("the water acts on the air") — the correct reasonfour reasons that END at the reason ("The wind did the acting, and the snow was moved.") — v2, the verdict no longer bundledwind drifts snow; rain beats rose petals

Hard because — type 4: the word is produced from a described box, not picked (the second from a box about shapes, not colors). Type 7: each belief is judged by its correct reason, which needs the lesson's idea (the wind is air; erosion; roots and diggers; evaporation from the sea) held against the belief. Type 8: the term is recalled from its definition on a fresh case with no clue word; the second item judges the term in use across four cases, two of them near misses. Type 10 hard: two steps happen in turn and the student must isolate the asked step — the part changed in step one is the part acting in step two, and the step-one actor is the trap. Type 11: the answer is a set, and lava must be sorted as land before the set can be found. Type 12: the direction of a claim is judged by its correct reason, with snow sorted as water first. (v2) Type 10 hard, the ash item: the acting material must be sorted as land before the pair can be found; the cloud of ash is the trap toward the air.

One exemplar per type, in full

Type 1 (easy, EAR4-026). A map of a park shows its paths, its pond and its woods. From which view does the map show them? — from the side / from underneath / from a hilltop far away / from straight above. Why: A map shows the land from straight above, as a bird flying high would see it. So a map shows the land from straight above. (nearest: L01-q2, "Which view of the land does a map show?" with three options — here a named map and four views)

Type 2 (easy, EAR4-026; figure pp_map_1). Letters J, K, L and M mark four things on this map. Which letter marks the town? — J / K / L / M. Why: In the legend, dark squares mean a town. One letter sits on the group of dark squares. So that letter marks the town. (nearest: L01-q3 and q4 on q_map_1 / q_map_2 with three letters — here four letters on a fresh layout: hills along the top, sea along the bottom)

Type 3 (medium, EAR4-026; figure pp_map_6). On this map, which way does the river run? — from the sea at the top to the hills on the right / from the lake to the forest / from the hills on the right to the sea at the top / from the forest to the towns. Why: The thin blue line is the river. One end touches the brown hills on the right, and the other end touches the sea at the top. Rivers carry the water back to the ocean, so the river runs from the hills to the sea. (nearest: L01-q7 on q_map_5, hills along the bottom and the sea at the right — here hills right, sea top)

Type 4 (hard, EAR4-026, typed). A map of a state park uses a star for the picnic tables and a triangle for the campsites. One box on the map says what the star and the triangle stand for. Type the name of that box. — accept: legend, the legend, a legend, map legend, the map legend, a map legend, key, the key, a key, map key, the map key, a map key, legand, ledgend, lejend, legund, legened, leggend. Hard because: the word is produced from a box about shapes, not colors. (nearest: L01-q10 and PR-14, "a box says what each color and shape stands for" — here a named map with named symbols)

Type 5 (easy, EAR4-080). A hailstone, a pond and a cloud all belong to one of Earth's four big parts. Which part do they belong to? — the air / the land / the water / the living things. Why: The water is the sea, the lakes, the rivers, the rain and the clouds. A hailstone is frozen water, a pond is water, and a cloud is made of tiny drops of water. So all three belong to the water. (nearest: L02-q4, a deer, a pine tree and a girl → the living things — here three water things, with the cloud as the thinking step)

Type 6 (medium, EAR4-080). Which of these is one part of Earth acting on another part? — a deer eats the leaves off a bush / warm air rises past cold air / a hot dry wind dries up a shallow pond in Texas / a big wave rolls over a small wave. Why: The wind is air, and the pond is water, so this is one part acting on another. A deer and a bush are both living things; warm and cold air are both air; two waves are both water. So only the wind and the pond is one part acting on another. (nearest: L02-q7, the hawk and the mouse as a yes / no — here four events in one item, three of them within one part)

Type 7 (hard, EAR4-080). Louis says a river and its banks are separate things, so the water never changes the land. Louis is wrong. What is the correct reason? — The banks change the river, not the other way round. / The river's water carries soil off its banks, so the water changes the land. / The river changes the land only when it is frozen. / The water changes the land only where people dig. Why: Erosion carries the broken pieces away to somewhere new. The river's water carries soil off its banks, so the water changes the land. So Louis is not right. (nearest: L02-q8, Luna's "separate places" as a bare yes / no — here the reason is picked)

Type 8 (hard, EAR4-080). Which sentence uses the word interaction correctly? — A robin pulling up a worm is an interaction between two of Earth's parts. / A tree's roots splitting a rock is an interaction between the living things and the land. / A map's legend is an interaction between the colors. / A still rock on a hill is an interaction between the land and the air. Why: An interaction is one part of Earth acting on another part and changing it. The roots (living things) change the rock (land), so that is an interaction. A robin and a worm are both living things, a legend is a box on a map, and a still rock changes nothing. (nearest: L02-q11 / PR-15, the term picked from its definition — here the term judged in use)

Type 9 (easy, EAR4-081; v2). A cold wind blows over a pond in Minnesota all night, and the top of the pond freezes. Which part of Earth is being changed? — the air / the land / the living things / the water. Why: The top of the pond freezes, so the pond is being changed. A pond is water. So the water is being changed. (nearest: L03-q2, the pines leaning — which part is being changed; here the air acts on water, a pair the lessons never asked)

Type 10 (medium, EAR4-081). Moss grows over a boulder in Vermont, and the rock's surface slowly crumbles under it. Which two parts of Earth act here? — the land acts on the living things / the water acts on the land / the living things act on the land / the air acts on the land. Why: Which part is doing the acting? The moss, a living thing. Which part is being changed? The boulder, which is land. So the living things act on the land. (nearest: L03-q6, prairie dogs dig → living things on land — here a plant crumbling rock, no digging)

Type 10, hard (EAR4-081; v2). A volcano in Washington throws out a cloud of ash, and ash is tiny pieces of rock. The ash settles on a lake and turns its water gray. When the lake turns gray, which two parts of Earth act? — the land acts on the water / the land acts on the air / the air acts on the water / the water acts on the land. Why: Ash is tiny pieces of rock, so ash is land. Which part is doing the acting? The ash, which is land. Which part is being changed? The lake, which is water. So the land acts on the water. Hard because: the acting material must be sorted as land before the pair can be found; the cloud of ash is the trap toward the air. (nearest: L03-q8, ash fills the air — one step; here two steps and the second is asked)

Type 11 (hard, EAR4-081, multi-select). Hot lava from a volcano in Hawaii flows over a forest and burns the trees. Select the TWO parts of Earth that act on each other here. — the land / the air / the water / the living things. Why: Lava is melted rock from deep inside Earth, so it is land. Which part is doing the acting? The lava, which is land. Which part is being changed? The trees, which are living things. So the two parts are the land and the living things. (nearest: none — no lesson item asks for a set)

Type 12 (hard, EAR4-081; v2). Wind blows the snow off a frozen field in North Dakota into tall drifts along a fence. Louis says the water acts on the air here. Louis is wrong. What is the correct reason? — The snow did the acting, and the wind was changed. / The wind did the acting, and the snow was moved. / The fence did the acting, and the snow was moved. / Nothing did the acting, and nothing was changed. Why: Which part is doing the acting? The wind, which is air. Which part is being changed? The snow, which is water. So the air acts on the water, and Louis is not right. (nearest: L03-q9, Josie's "the land acts on the water" on waves and sand as a bare yes / no — here the reason is picked, and snow must be sorted as water)

⟂ draw constraints (never in one twenty-item draw)