Skill: course-build → write-mcqs → write-explanation, design-check-sequence @ df153ae; v2 (reviews applied, 2 Oct 2026) → write-mcqs, write-explanation @ b0fa825
Topic 5 — What happens when things bump into each other — the PP100's question types, one exemplar each
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). The bank in content/G4T05_pp100_bank.py holds 51 items (20 easy, 21 medium, 10 hard), every item tagged to ONE atom, built from the seventeen types below; the type number sits on each item as type_. Under the standing Grade 4 brief the bank is built straight away; this sheet is the first thing to read, and a type James strikes takes its items out of the bank.
v2 (2 Oct 2026). The guidance review found the v1 claim "every item a fresh instance" false: about twenty items reused the lessons' marbles, carts, hammer-and-nail, ramp-and-truck, ball-and-cup, golf-ball, coin, skateboard, bumper-car, bike and can scenes with a noun changed. Every one of them is now on a scene no lesson, quiz, attached, practice or summary item uses (the reviewer's list — bocce balls, croquet balls, ping-pong balls, checkers, a barrel into a fence, a toy train into a shoe box, a beach ball into a lawn chair, a roller skate into a shoebox, a rubber mallet on a tent peg, a kick-scooter into a cone, a toy ambulance into a stack of cups — plus the author's: suitcases, pine cones, sliding books, softballs, kickballs, apples, beads, desk chairs, hula hoops, melons, a ball of yarn, walnuts, canoes, metal buckets, a wheelbarrow and a shed door, a toy tractor and a tissue box, a lemon and an egg carton, toy buses and erasers, pool balls, snowballs, train cars that hook together, toy jeeps and juice boxes, toy taxis and chalk boxes). Two typed items became MCQs (PP-41 "warmer", PP-49 the fastest of three rolls) because their typed keys were not closed; PP-49 (v1: a reading plus a subtraction with no energy idea) was cut; the two-trucks drawing became two toy trains with no motion lines.
Coverage. ENE4-004 (L01) 14 items · ENE4-005 (L02) 13 · ENE4-006 (L03) 13 · ENE4-010 (L04, the capstone) 11. Easy sits mostly on the early atoms, hard mostly on the capstone (checker S31 clean). Typed items: 1 text (PP-46), 1 numeric (PP-48); 1 multi-select (PP-47); 48 four-option MCQs. Keys: A 12 · B 12 · C 12 · D 12 (25 % each of the single-key MCQs; no run of four, no A-B-A-B alternation); key string BACDCBAADDADBAACDDBCCBADDBBCDCADDCBBCDABACABCBAC. No key is the longest option by shape (v2: PP-14, 24, 30, 32, 33, 38, 50 trimmed or their distractors lengthened).
Bar list (real things a generated item must never claim): no item says a push "runs out" or "wears off" (catalogue FOR-01), none measures a push by how far a thing went (FOR-12: every speed-and-slide item names the roll's speed or lets the mover go; no push is ever "harder"), none calls sound "a form of energy" (ENE-06), none says energy is "used up" or "gone" except as a distractor (ENE-03); no still thing is said to "have no energy" (ENE-02 — "no kinetic energy" is Grade 3's accepted wording); "lost" appears nowhere, even in a why (v2: PP-32's why).
| Type | Atom | Tier | The stem asks… | The four options are… | Exemplar |
|---|---|---|---|---|---|
| 1 | ENE4-004 | easy / medium | where the energy for the struck thing's moving came from, or which thing handed energy over, or why the giver is slower | four sources: the mover (key), the struck thing itself, the ground / floor, the air / water | PP-1 |
| 2 | ENE4-004 | easy | which of four things is handing over energy (one moving thing that hits; three still things), or which sentence says what a moving object does at a hit | four scenes, or four one-clause statements | PP-2 |
| 3 | ENE4-004 | easy (recognition) / hard (the term applied to cases, by MCQ) | the name for a moving object bumping into another object; which of four cases is a collision | collision and its sister words (slide, force, push) — never typed (RECALL_BY_MCQ); four cases, three near misses | PP-6, PP-43 |
| 4 | ENE4-005 | easy / medium | what the still object does after the hit, or which sentence says what BOTH objects do (a case, never the bare rule) | starts moving (key) / stays still / moves only after the other stops / rolls toward the mover; or the 2 × 2 grid of moves / stays × slows / speeds | PP-10, PP-14 |
| 5 | ENE4-005 | easy / medium | what the moving object does right after the hit, or which object has more / less energy than before | slows down (key) / speeds up / keeps the same speed / turns around | PP-11 |
| 6 | ENE4-005 | easy | a prediction from a BEFORE card (the drawing shows the rolling thing and the still thing; nothing has happened yet) | four outcomes for the still thing | PP-15 (fig q_before_bocce) |
| 7 | ENE4-006 | easy / medium | what carries energy from a crash to your ears; what happens to the two things' warmth; how a struck thing feels after many hits | sound (key) / light / the struck thing / electricity; warmer (key) / colder / no change / one each | PP-16, PP-41 |
| 8 | ENE4-006 | medium | where the energy for a warm struck thing came from | four sources, one the moving striker | PP-29 |
| 9 | ENE4-006 | medium | where the rest of the energy went, or which sentence about a crash is true | four destinations / four statements, with the catalogue's "gone", "used up", "made" beliefs as the distractors | PP-30 |
| 10 | ENE4-006 | hard, TEXT | the carrier that takes energy from the crash to your ears, produced | accept: sound / noise / clang forms, and Grade 3's vibration(s) and the air | PP-46 |
| 11 | ENE4-010 | easy / medium | which roll or which mover handed over more energy, or was faster, from two slides (described, or drawn with rulers) | the two movers / both the same / you cannot tell | PP-19, PP-39 (fig pp_slides_two_trains) |
| 12 | ENE4-010 | medium | what to measure for the evidence; what must stay the same for a fair test | four measurements / four lists | PP-37, PP-38 |
| 13 | ENE4-004 / 005 / 010 | hard | a judgement on an unshown shape of the rule: the giver that stops at once; the pair that hooks together and rolls on; the energy before and after as a share; equal slides | four statements, one true | PP-42, PP-44, PP-45, PP-51 |
| 14 | ENE4-006 | hard, MULTI | the TWO places some of the energy goes in a crash (the answer is a set) | sound and warmth (keys) / light / extra speed | PP-47 |
| 15 | ENE4-010 | hard, NUMERIC | read the evidence off a drawn ruler: the faster train's slide | typed centimeters, the unit optional, the word form accepted | PP-48 (fig pp_slides_two_trains) |
| 16 | ENE4-010 | hard | the fastest of three rolls from three slides, where the longest slide is not the last | the three rolls / you cannot tell | PP-49 |
| 17 | ENE4-010 | hard | which sentence is the evidence for a stated claim about which mover was faster | four candidate evidence sentences, two stating the opposite or an irrelevant fact | PP-50 |
Hard because (one line per hard item). PP-42: two ideas judged on a giver that stops ("stopped means gone" trap). PP-43: the coined term applied to four cases, three near misses (MCQ because RECALL_BY_MCQ). PP-44: the rule on a pair that hooks together and rolls on — a shape never shown. PP-45: the hand-over traced as a before / after share. PP-46: the carrier produced, not picked. PP-47: the answer is a set. PP-48: pick the faster train from the evidence, then read its slide. PP-49: three slides ranked; the longest is the middle one. PP-50: the evidence sentence for a stated claim chains slide → energy → speed. PP-51: the rule run backward on equal slides.
The exemplars, in full
Type 1 — PP-1 · ENE4-004 · easy
Stem: A rolling log bumps into a still log at the edge of a stream, and the still log starts to roll. Where did the energy for the still log's rolling come from?
- a) from the still log itself · b) from the rolling log ← key · c) from the ground · d) from the water
Why: A moving object hands over some of its energy to whatever it hits. / The rolling log hits the still log. / So the energy for the still log's rolling came from the rolling log.
Type 2 — PP-2 · ENE4-004 · easy
Stem: Which of these is handing over energy to something it hits?
- a) a ball rolling into a wall ← key · b) a book lying on a shelf · c) a chair standing by a desk · d) a bucket sitting in a corner
Type 3 — PP-6 · ENE4-004 · easy (recognition); PP-43 · hard (the term applied)
PP-6 stem: A moving object bumps into another object. What is this bump called? — a) a slide · b) a collision ← key · c) a force · d) a push
PP-43 stem: Which of these is a collision? — a) a rolling barrel bumping into a fence ← key · b) a ball rolling past a cone · c) a ladder leaning on a wall · d) a kite flying in the wind
Type 4 — PP-10 · ENE4-005 · easy; PP-14 · easy (the two-part outcome as a case)
PP-10 stem: A rolling ping-pong ball hits a still ping-pong ball on a table. What does the still ball do?
- a) It rolls toward the rolling ball. · b) It stays still. · c) It moves only after the rolling ball stops. · d) It starts moving. ← key
PP-14 stem: A rolling kickball bumps into a still kickball on the playground. Which sentence is true?
- a) The still ball rolls, and the first ball slows down. ← key · b) The still ball rolls, and the first ball speeds up. · c) The still ball stays still, and the first ball slows down. · d) The still ball stays still, and the first ball speeds up.
Type 5 — PP-11 · ENE4-005 · easy
Stem: A rolling croquet ball hits a still croquet ball on the grass. What does the rolling ball do right after the hit?
- a) It slows down. ← key · b) It speeds up. · c) It keeps the same speed. · d) It turns around and rolls back.
Type 6 — PP-15 · ENE4-005 · easy · fig q_before_bocce (a BEFORE card: nothing has happened yet; never the animation)
Stem: The drawing shows a rolling bocce ball and a still bocce ball on a lawn. What will the still ball do after the hit?
- a) It will start moving. ← key · b) It will stay still. · c) It will roll toward the rolling ball. · d) It will spin in one place.
Type 7 — PP-16 · ENE4-006 · easy; PP-41 · medium (v1's typed "warm", re-typed)
PP-16 stem: A rolling barrel bumps into a wooden fence with a thud. What carries energy from the bump to your ears?
- a) the light · b) the fence · c) the sound ← key · d) electricity
PP-41 stem: Camden taps a tent peg into the ground with a rubber mallet, twenty taps in a row, and then touches the top of the peg. Compared with before the taps, how does the top of the peg feel?
- a) warmer ← key · b) colder · c) the same · d) wet
Type 8 — PP-29 · ENE4-006 · medium
Stem: Camden claps two wooden blocks together many times, and then the blocks feel warm. Where did the energy for the warming come from?
- a) from the air · b) from the floor · c) from the light in the room · d) from the moving blocks ← key
Type 9 — PP-30 · ENE4-006 · medium
Stem: A rolling walnut clicks into a still walnut on a table, and the still walnut rolls only a short way. Where did the rest of the rolling walnut's energy go?
- a) It is gone. · b) Back into the rolling walnut. · c) Into the click's sound and into warmth. ← key · d) Into the light around the walnuts.
Type 10 — PP-46 · ENE4-006 · hard · TEXT
Stem: Two metal pans clang together. Some of the energy is carried from the crash to your ears. Type the name of what carries it.
Accept: sound, the sound, a sound, sounds, noise, the noise, a noise, the clang, a clang, clang, sound waves, the sound waves, vibrations, vibration, the vibrations, sound vibrations, the air, air.
Hard because: the carrier is produced, not picked, from a scene that names only the clang. (v2: the stem no longer prints "Some of the energy warms the pans", which gave PP-41 away.)
Type 11 — PP-39 · ENE4-010 · medium · fig pp_slides_two_trains
Stem: The drawing shows two matching toy trains that each hit a matching shoe box on a matching floor. Which train handed over more energy?
- a) the first train ← key · b) the second train · c) both the same · d) you cannot tell
Type 12 — PP-38 · ENE4-010 · medium
Stem: Brielle rolls a lemon into an empty egg carton at two speeds, to see which speed hands over more energy. To make the test a fair test, which things must stay the same?
- a) only the egg carton · b) only the lemon's speed · c) the lemon's speed and the floor · d) the carton, the lemon and the floor ← key
Type 13 — PP-44 · ENE4-005 · hard
Stem: A rolling toy train car hits a still toy train car. The two cars hook together and roll on at one speed. Compare that speed with the first car's speed before the hit.
- a) faster than before · b) slower than before ← key · c) the same as before · d) twice as fast as before
Hard because: the rule applied to a case where the giver does not stop and the two move on together — a shape the lessons never showed. (v2: train cars that hook, because marbles do not roll on together.)
Type 14 — PP-47 · ENE4-006 · hard · MULTI (two of four)
Stem: A beach ball thuds into a folding lawn chair and bounces back more slowly. Select the TWO places some of the ball's energy went.
- a) into light from the chair · b) into the sound of the thud ← key · c) into warming the ball and the chair ← key · d) back into the ball as extra speed
Type 15 — PP-48 · ENE4-010 · hard · NUMERIC · fig pp_slides_two_trains
Stem: The drawing shows two matching toy trains that each hit a matching shoe box. Which train was faster? Read how far ITS box slid. Type the number of centimeters.
Accept: 30, 30 cm, 30cm, 30 centimeters (the singular and British forms), thirty, thirty centimeters, thirty cm.
Hard because: two steps — pick the faster train from the evidence, then read its box's slide off the drawn ruler.
Type 16 — PP-49 · ENE4-010 · hard
Stem: The same roller skate rolls into the same shoebox three times. The box slides 10 centimeters, then 30 centimeters, then 20 centimeters. In which roll was the skate moving fastest?
- a) the first roll · b) the second roll ← key · c) the third roll · d) you cannot tell
Hard because: three slides to rank, and the longest is the middle one, not the last.
Type 17 — PP-50 · ENE4-010 · hard
Stem: Brielle rolls a red toy jeep and a blue toy jeep, matching jeeps, into matching juice boxes. The red jeep's box slides farther. Brielle says the red jeep was the faster jeep. Which sentence is the evidence for what Brielle says?
- a) The red jeep's box slid farther. ← key · b) The red jeep rolled first. · c) The blue jeep's box slid farther. · d) Both boxes slid the same distance.
Design-move inventory (every item's move, scene and nearest lesson-side instance)
The lessons' own instances (never a bank scene): the bowling ball and pins; the gutter miss; the shopping cart and the parked cart; the two marbles on the classroom floor (L02 and L03); the toy cars; the skateboards; the hammer and the nail; the dropped-and-bounced basketball (L03 FRQ); the toy truck on the ramp and the wooden block; the tennis ball and the cup (L04 FRQ); the quiz scenes (trash can, golf balls, sled and snowman, bike on a wall, wagon and gate, ball and box, coins, hockey pucks, carts BEFORE card, bowling ball pair, soccer balls, lunch boxes, bumper cars, thumbtack, tray, bikes, the dropped spoon, yellow and green balls into cups, bottle caps, skateboard into a box); the practice scenes (sled and fence post, oranges, baseball and bat, toy cars, the single ruler lane, a toy fire truck and a cereal box, scooter, sleds, boats, the dropped book, the cans); the summary scenes (soup cans, shopping carts' clang, red and blue balls into cups).
| Item | Move | Scene | Nearest earlier instance |
|---|---|---|---|
| PP-1 | source of the struck thing's energy | logs at a stream | L01 q1 (skateboard, trash can): same move, new scene |
| PP-2 | pick the one thing handing over energy | four things, one rolling into a wall | L01 q2–q5 (yes / no per case): the four-way form is new |
| PP-3 | which thing hands over | ice cubes on a tray | PP-1 |
| PP-4 | true statement about a bump | tire and trash can | new form (Leave, reviewer 2 Oct) |
| PP-5 | source of the struck thing's energy | suitcases at an airport | PP-1 (v2: was a second four-way, near-duplicate of PP-2) |
| PP-6 | term recognition | none (description) | L01 q9: no scene here |
| PP-7 | which thing hands over | pine cones on a sidewalk | PP-3 |
| PP-8 | the rule's statement among wrong ones | none | new |
| PP-9 | energy of the giver after | pumpkins | L01 q7 (ball and box) |
| PP-10 | still one after | ping-pong balls | L02 q1 (coins) |
| PP-11 | moving one after | croquet balls | L02 q2 |
| PP-12 | still one, a moment after (what is it doing) | sliding books | PP-10, surface varied |
| PP-13 | moving one, compared with before | softballs | PP-11, surface varied |
| PP-14 | the two-part outcome as a 2 × 2 case | kickballs | L02 q5 (v2: was the bare rule) |
| PP-15 | predict from a BEFORE card | bocce balls drawn on a lawn | L02 q3 (carts drawn): new drawing, new scene |
| PP-16 | the carrier to the ears | a barrel into a fence (thud) | L03 q1 (bumper cars) |
| PP-17 | warmth after a crash | generic two things | L03 q6 (bikes) |
| PP-18 | true statement about a click | pool balls | new |
| PP-19 | which roll moves the box farther | toy tractor, tissue box | L04 q9 (skateboard and box) |
| PP-20 | more or less energy handed over | roller skates, shoebox | L04 V1 |
| PP-21 | why the giver is slower | balls of yarn | L02 FRQ (soccer balls) |
| PP-22 | what the giver handed to | ball and wall | new ("the ceiling" is the inert distractor, v2) |
| PP-23 | a chain of two hand-overs | three checkers | new |
| PP-24 | the two-part outcome applied | apples on a table | L02 q5 |
| PP-25 / 26 | which has more / less than before | beads; desk chairs | L01 q7 |
| PP-27 | a wrong prediction corrected | hula hoops | L02 q7 (claim form) |
| PP-28 | what happened to the giver | melons | L02 q2 |
| PP-29 | source of a warm thing's energy | clapped blocks | L03 q2 (thumbtack) |
| PP-30 | where the rest went | walnuts' click | L03 headache (the article's own question; the bank item carries the destinations as options) |
| PP-31 | what warmed them | canoes at a dock | L03 q6 |
| PP-32 | true statement about a clank | metal buckets | PP-18 (draw one per test) |
| PP-33 | the destinations as a list | a toy ambulance into paper cups | L03 article (the taught case; the list form is new) |
| PP-34 | the carrier named by its sound word | a wheelbarrow into a shed door (bang) | L03 q5 (tray clatter) |
| PP-35 | true statement about a crash | none | L03 q8 |
| PP-36 | which roll was faster, from described slides | kick-scooter and cone | L04 FRQ (tennis ball and cup) |
| PP-37 | what to measure | toy tractor, tissue box | new |
| PP-38 | fair-test constants | lemon, egg carton | L04 q4 (what changes) |
| PP-39 | which handed over more, from a drawing | two toy trains drawn, shoe boxes | L04 q2 (yellow and green balls): new drawing |
| PP-40 | which had more energy, from described slides | toy buses, erasers | PP-36 (draw one per test) |
| PP-41 | how the struck thing feels after many hits | rubber mallet, tent peg | L03 q2 |
| PP-42 … PP-51 | the hard tier, listed above | pool balls; barrel and fence (among four cases); train cars; snowballs; pans; beach ball and lawn chair; toy trains drawn; roller skate and shoebox; toy jeeps and juice boxes; toy taxis and chalk boxes |
Draw constraints (⟂) — never together on one test
Give-aways (a later item prints an earlier item's answer): PP-8 ⟂ every type-1 item (PP-1, 3, 5, 7, 21, 22, 23) — PP-8's key is the rule those items apply · PP-14 ⟂ types 4 and 5 (PP-10, 11, 12, 13, 24, 25, 26, 27, 28, 44) — its grid states both halves · PP-24 ⟂ PP-10, 11, 12, 13 (same reason) · PP-30 ⟂ PP-46, PP-47 — its key lists the carrier and the warmth · PP-33 ⟂ PP-46, PP-41 · PP-35 ⟂ PP-30, PP-32, PP-42 — "every bit went somewhere" is their trap's correction · PP-17 ⟂ PP-31 — PP-31's stem says the canoes got warmer · PP-42 ⟂ PP-18 — PP-42's why names the click's sound · PP-19 ⟂ PP-37 — the tractor and the tissue box: PP-19's stem says the slide is what varies · PP-20 ⟂ PP-49 — the roller skate and the shoebox · PP-16 ⟂ PP-43 — the barrel bumping the fence is PP-43's key case · PP-48 ⟂ PP-39 (one drawing; PP-39 names the first train, PP-48 reads its slide).
Same-move pairs (draw one per test): PP-2 ⟂ PP-5 (energy source, four-way vs one scene) · PP-3 ⟂ PP-7 · PP-18 ⟂ PP-32 · PP-36 ⟂ PP-40 · PP-6 ⟂ PP-43 · PP-10 ⟂ PP-12 · PP-11 ⟂ PP-13 · PP-25 ⟂ PP-26.
Shared scenes with no give-away (allowed together, noted): PP-14 and PP-47 do not share (kickballs; beach ball and chair). No other two bank items share a scene.
⟂ added after the v2 re-read (2 Oct 2026): PP-39 ⟂ PP-48 (one drawing, the same train answers both).