Topic 2 — How to run a fair test — blueprint for James
What I need from you: 4 decisions
Does one investigation run through all six lessons, with the quiz scenes fresh each time?
the topic is one chain, from a question the class can test to the friction result; the register's own example for the last atom is the same toy car on tile, wood and carpet.
your demo notes of 2 October asked for the full context at the top of every video, so each lesson re-sets the car-and-floors scene in its first beat.
My recommendation: one investigation (which floor lets the same toy car slide farthest?), re-set in every first beat; the quizzes use fresh tests (plants, paper towels, paper planes, ice cubes). One investigation / a new scene per lesson.
Is "fair test" the only term coined, with the three parts kept as plain phrases?
the register keeps "variable", "independent", "dependent" and "control" for grades 6-8; the three parts are "the one thing you change", "what stays the same" and "what you measure".
"fair" has a second everyday reading (kind, not cheating); the coining line says what it means here: only one thing was changed.
My recommendation: yes; "fair test" coined in L05 as "a test where only one thing is changed", used whole from then on. Yes / coin the parts too.
Does L06 end with the class's results, so Topic 1's prediction is checked?
the atom is "plan a test"; the plan alone leaves the child with no answer to the question the topic opened on.
a short results table (tile 180 centimeters, wood 150, carpet 40) closes the loop and gives the first table the child reads in Grade 4.
My recommendation: plan, then the results table, then the one-line answer. Plan and results / plan only.
Which lessons get a video?
L02, L03, L04 and L06 show the car released from the ramp on each floor and the tape measure laid out; L01 and L05 are sorts of written questions and tests.
My recommendation: all six scripted; L01 and L05 marked "could do without". All six / L01 and L05 article only.
Topic 2 at a glance — 6 lessons
| Lesson | Opens on | Format | |
|---|---|---|---|
| L01 | A question you can test | Miss Alvarez's class wants to know something about the floors in their school. | little; two questions on a board and a hand sorting them — could do without a video (decision 4). |
| L02 | The one thing you change | Miss Alvarez's class is testing which floor lets the same toy car slide farthest. | video + article |
| L03 | Keep everything else the same | On the carpet, Felipe gives the car a push as it leaves the ramp. | video + article |
| L04 | What you measure to see the result | The class has released the car the same way on each floor. | video + article |
| L05 | Fair test or unfair test? | Another class tests two bean plants to see whether more water makes a plant grow taller. | little; two plants with two differences highlighted, then one — could do without a video (decision 4). |
| L06 | Test friction on different floors | Miss Alvarez's class is ready to find out which floor lets the toy car slide farthest. | video + article |
What this topic is, in five lines
Six lessons, one per atom: SR4-001, 002, 003, 004, 005, FOR4-004.
Term coined here: fair test (L05).
Deliberately not taught: variables by name (grades 6-8); why an unfair test tells you nothing, as an explanation (practised here, explained in grades 6-8); planning the whole test from scratch (Grade 5, SR5-002); comparing two designs (Grade 5).
PP100 cluster: the whole topic, capstone FOR4-004 (the planned friction test carries the five parts).
Applied without asking (rulings you have already given): one atom, one lesson, video and article; the example sequence for every sort, near-miss non-examples only, the rule last; the headache asks about the happening; a fluency quiz after the coining lesson, recognition before recall, "fair test" chosen before it is typed; one attached easy question after "Okay, now your turn" on every lesson video and three on the summary; the intro at most 120 words with a ready line and a poll; the summary at most 175 words opening "Here's everything we found out about how to run a fair test"; the Grade 3 measuring routines (a tape measure in centimeters; pick the tool by asking what you want to know) recalled by one item, never re-taught; "Two groups, two different answers" (Grade 3) recalled in L04; units as words; every student sentence has a subject and a verb; names a child can spell, one topic each (Miss Alvarez's class: Felipe, Niall, Maeve); US spelling; colour drawings by code; the results table introduced as a table.
Misconceptions and traps (atomise step 3)
| Trap | Where this topic meets it |
|---|---|
| changing two things at once and reading the result as the answer | confront in L05: the near-miss unfair tests (one plant gets more water and more light) are the non-examples; the claim item "Niall says the test was fair because both plants got water" |
| "fair" read as kind or not cheating (second everyday reading) | avoid by wording: the coining line in L05 says what fair means here; "fair test" is said whole, never "fair" alone |
| the question that cannot be tested ("which is best?", "which is nicest?") taken as a test question | confront in L01: the near-miss non-examples are questions a child really asks |
| measuring something other than what the change did (timing the push instead of measuring the slide) | confront in L04: the quiz's wrong measurements are plausible ones |
A question you can test L01
Miss Alvarez's class wants to know something about the floors in their school.
Felipe writes on the board: which floor is the best?
Niall writes under it: which floor lets our toy car slide farthest?
The class can try out only one of these questions.
Which question can the class answer by trying it out?
Niall's question names something the class can do and watch: slide the car and see how far it goes.
Felipe's question does not, because "best" is an opinion and nobody can try out an opinion.
A question you can answer by trying something out and watching what happens is a question you can test.
Video: little; two questions on a board and a hand sorting them — could do without a video (decision 4).
Part 1 — SR4-001 — Decide whether a question can be answered by trying it out
The one thing you change L02
Miss Alvarez's class is testing which floor lets the same toy car slide farthest.
Maeve releases the car from the top of a small ramp onto the tile floor.
Then the class carries the ramp to the wooden floor and releases the car again.
Then the class carries the ramp to the carpet and releases the car once more.
What is the one thing the class changes from one go to the next?
The floor changes: tile, then wood, then carpet.
The class changes the floor on purpose, because the floor is what the question asks about.
In a test, the one thing you change on purpose is the thing your question asks about.
Video: the same ramp and car moved from floor to floor, the floor lighting up each time — video and article.
Part 1 — SR4-002 — Identify the one thing changed on purpose in a described test
Keep everything else the same L03
On the carpet, Felipe gives the car a push as it leaves the ramp.
The car goes farther on the carpet than it did on the tile.
Niall says the carpet must let the car slide farthest.
Maeve says something went wrong.
Why can the class not trust this result?
Two things changed between the tile and the carpet: the floor, and the push.
Now nobody can tell which one made the car go farther.
So everything except the one thing you change must stay the same: the same car, the same ramp, the same release with no push, the same starting point.
Video: the extra push shown and then crossed out; the same release repeated on each floor — video and article.
Part 1 — SR4-003 — Identify what must stay the same in a test for the result to mean anything
What you measure to see the result L04
The class has released the car the same way on each floor.
Now they need to say which floor let the car slide farthest.
Maeve wants to time how long the car moves.
Niall wants to measure how far the car slid, from the bottom of the ramp to where it stopped.
Which measurement answers the class's question?
The question asks how far the car slides, so the class measures the distance it slid, in centimeters, with a tape measure.
The measurement must match what the change did: a different floor changes how far the car goes.
What you measure to see the result is the thing your question asks about, after the change.
Video: the tape measure laid from the ramp's foot to the car, the reading appearing in centimeters — video and article.
Part 1 — SR4-004 — Identify what to watch or measure to see what the change did
Fair test or unfair test? L05
Another class tests two bean plants to see whether more water makes a plant grow taller.
Felipe gives one plant more water and puts it on the sunny windowsill.
The other plant gets less water and sits in the dark corner.
The plant on the windowsill grows taller.
Can the class say that the water made the difference?
No, because two things changed at once: the water and the light.
Nobody can tell which one made the plant grow taller.
A test where only one thing is changed, and everything else stays the same, is called a fair test.
This test changed two things, so it is not a fair test.
Video: little; two plants with two differences highlighted, then one — could do without a video (decision 4).
Part 1 — SR4-005 — Decide whether a described test is fair by checking that only one thing was changed; coin fair test
Part 1q — Fluency quiz: fair test
Test friction on different floors L06
Miss Alvarez's class is ready to find out which floor lets the toy car slide farthest.
Before they start, Miss Alvarez asks them to write the plan on the board.
What goes on the board, so that the test is a fair test?
The question: which floor lets the same toy car slide farthest?
The one thing we change: the floor (tile, wood, carpet).
What we keep the same: the same car, the same ramp, the same release with no push, the same start line.
What we measure: how far the car slides, in centimeters, with a tape measure.
Then the class runs the test and writes the distances in a table: the car slid farthest on the tile and least far on the carpet, as Topic 1 predicted.
Video: the plan filling in line by line, then the three runs and the table filling with the three distances — video and article.
Part 1 — FOR4-004 — Plan a test comparing how far the same object slides on different surfaces, as a fair test
Questions the blueprint cannot settle alone
- Whether the intro's scene is the two questions on the board or the car already sliding on two floors; both coin nothing. My call is the car on two floors, so the question "how would you find out?" is the curiosity gap.
- Whether L06's results table uses the class's distances (made up but plausible: 180, 150 and 40 centimeters) or asks the child to predict the order first and then shows it. My call is predict first, one item, then the table.
This grade’s course architecture — open only if you want the whole map
Skill: course-build → atomise (architecture re-check, steps 6b/6c) → write-like-james @ df153ae
Grade 4 Science — course architecture v2 (re-checked 2 October 2026 against every ruling since 28 September)
Status: PROVISIONAL — in force from 2 October 2026 under James's ruling "build straight away"; any line he objects to is changed, nothing waits for a click.
Read this in five minutes. Grade 4 Science is ONE course with a fixed order, built the same way as Grade 3. It arranges the 158 Grade 4 atoms into five strands and thirty-eight small topics, each with its own summary video, mixed practice and PP100. Nothing below writes a lesson sentence. The atoms stay where they are: the Science Knowledge Graph's 3-5 registers. Every atom is placed exactly once; no atom's prerequisite comes after it (checked again on 2 October, see "Checks run").
Decisions I need from you
The first two changed since the 28 September plan. The other four are the 28 September questions, still open, with the same recommendations. I am building on every recommendation below; say so if you want any of them the other way.
1. Is engineering design its own strand in Grade 4, two topics long, placed after Physics?
Context: you said on 1 October "in Grade 4 we may want to consider it as a separate strand". The Grade 4 design atoms are four: what a design must do, what it must stay inside, design a solution, test the design against the rule.
Context: the three-lesson demo you reviewed on 2 October (the bird feeders) already teaches the first three, in the course schema, videos rendered. The fourth needs the fair test (Topic 2) and a real build to test, and the energy-changer build (NGSS 4-PS3-4, "design, test and refine a device that converts energy") is that build.
Recommendation: a fifth strand, "Design and build", of two topics after Physics: Topic 11 is the demo as built (3 lessons); Topic 12 "How to build and test an energy changer" (4 lessons: moving air and water turn things, spot the energy change, build the changer, test it against the rule). The 28 September plan's seven-lesson Topic 11 goes away. The strand gets its own short intro video and NO end-of-strand test (two PP100s certify seven atoms).
Choices: fifth strand as recommended / weave the four atoms into Physics as one seven-lesson topic (the 28 September plan) / fifth strand but with a strand test too.
2. Does the summary video come before the mixed practice in Grade 4?
Context: for the demo on 2 October you ruled "the summary comes BEFORE the mixed practice". Grade 3 runs practice → summary → PP100 (the 25 September ruling for grades 3-8).
Context: with the summary first, the child hears every rule once, then practises, then sits the PP100 with the practice fresh. The page order is a one-line flag per topic; Grade 3 is untouched until you say.
Recommendation: yes, summary → practice → PP100 for Grade 4.
Choices: yes / keep Grade 3's order (practice → summary → PP100) / change Grade 3 too.
3. Does Grade 4 physics open straight on friction, with retrieval items from Grade 3 instead of a re-teach?
Context: Grade 4 has no motion atoms and nothing re-teaches balanced and unbalanced forces; friction's only prerequisite is Grade 3's "a push or pull can slow or stop things".
Context: Olivia asked for cross-grade retrieval; two or three Grade 3 items in Topic 1's practice set give it without a re-teach lesson.
Recommendation: friction first; retrieval items only.
Choices: as recommended / a re-teach topic with new atoms.
4. Is the fair test taught on the friction investigation (Topic 2)?
Context: "test friction on different surfaces" needs "keep everything else the same", so the five fair-test lessons come just before it, in one six-lesson topic that is one investigation from question to result.
Recommendation: yes, Topic 2 as drawn.
Choices: yes / move the fair test to the energy-changer build.
5. Does "water's states at work" stay in Matter, next to "same material or new material"?
Context: Matter uses water freezing, melting and evaporating as its reference case for "same material, changed". The water cycle (Topic 23) uses the same idea seven topics later and retrieves it in one line.
Recommendation: keep it in Matter.
Choices: keep / move to open the water cycle.
6. Do the three energy-resource topics sit in Earth & Space, after the water cycle and climate?
Context: wind, moving water, sunlight, plants and the three fuels are Earth's resources (TEKS 4.11, Florida 4.E.6.3); the one Physics atom among them (moving air and water can turn things) is taught in Topic 12.
Recommendation: Earth & Space, as drawn.
Choices: Earth & Space / end of Physics.
Applied without asking (your rulings already given): the strand order Physics → Matter → Earth & Space → Life, with Design and build slotted after Physics (decision 1); Scientific Reasoning taught inside the topics that use it, no SR strand test; topics of three to six atoms, none over six; the water cycle taught once, here, with the ocean; the Moon "why" atom in, seasons patterns-only; one atom one lesson, video or article; an intro per strand and per topic that teaches nothing; "criterion" and "constraint" ARE coined in Grade 4 and used from then on (your demo notes of 2 October: "we already have introduced criterion and constraint so that's what we should be using now"), so the register's SR4-021 note "everyday wording only" is proposed for retirement in the knowledge-graph repo; the pattern-and-predict practice sits where the pattern is the science (the Sun's path, the seasons, the Moon's shapes, which are already atoms there), with "a pattern is something that happens again and again in the same way"; predator and prey are Grade 5 words, Grade 4 says "the fox eats the rabbit"; every topic title fits the frame "Here's everything we found out about ___"; the language rules (Earth's pull, carriers not forms, no "leak" or "lift", "stuff" beside "matter", "density" named); grade-4 codes that restate grade-3 content are cited on the grade-3 atoms, no clones; the strand tests are placeholders until Becky's format gate is passed (Grade 3's proposal of 30 September applies as written); names a child can spell, one topic each, US animals, US spelling; "strand" never said to a student.
Card 1 — The strands and their order
The call: Physics → Design and build → Matter → Earth & Space → Life, each with its own intro video; a strand test after Physics, Matter, Earth & Space and Life (placeholders under Becky's validation), none after Design and build.
| Strand | Topics | Atoms | Why it sits here |
|---|---|---|---|
| Physics | 1-10 | 38 (+5 Scientific Reasoning) | Forces first (friction, magnets), then Energy; the fair test is learnt on friction and used all year; waves come before Earth's seismic waves need them. |
| Design and build | 11-12 | 3 (+4 Scientific Reasoning) | Needs the fair test (Topic 2) and energy transfer (Topic 4); the energy-changer build is the design the child tests. |
| Matter | 13-16 | 13 | Mixtures and "the mass holds" feed Grade 5's conservation chain; "water's states at work" is banked before the water cycle. |
| Earth & Space | 17-32 | 66 (+3 Scientific Reasoning) | The biggest strand: rocks, slow changes, layers, the water cycle, climate, energy resources, the sky; rock layers must precede Life's fossil reading. |
| Life | 33-38 | 26 | Ends the year; leans on Earth (rock layers, fossils) and Grade 3 Life. |
Scientific Reasoning's 12 atoms are spread through Topics 2, 11, 12 and 25 (Card 3). Total 158 lessons.
Card 2 — The topics
The call: thirty-eight topics of three to six lessons; a summary video, a mixed mastery practice set and a PP100 at the end of every one. Every topic is one PP100 cluster, closed by the capstone atom named in the last column.
| # | Topic (student-facing title) | Atoms (in teaching order) | Lessons | The big idea it serves | PP100 capstone |
|---|---|---|---|---|---|
| Physics | |||||
| 1 | Why sliding things stop | FOR4-001, 002, 003, 005 | 4 | Where two surfaces rub there is a force against sliding: friction; a smoother surface lets things slide farther; friction helps and hinders | FOR4-005 helpful or unhelpful friction (the sort) |
| 2 | How to run a fair test | SR4-001, 002, 003, 004, 005, FOR4-004 | 6 | A question you can test; change one thing; keep the rest the same; measure the result; fair or unfair; then test friction on different surfaces for real | FOR4-004 the friction test (the routine run) |
| 3 | How magnets push and pull | FOR4-010, 011, 012, 013, 014 | 5 | Only some metals; two poles; like poles push apart, unlike pull together; closer is stronger; draw the force | FOR4-014 model a magnetic force |
| 4 | How energy moves from one thing to another | ENE4-001, 002, 003 | 3 | Energy passes from a giver to a receiver; light, sound, electricity and heat carry it; some carriers need no touch | ENE4-003 transfer without touching |
| 5 | What happens when things bump into each other | ENE4-004, 005, 006, 010 | 4 | A moving object hands over energy when it hits; predict the collision; the sound and warmth are energy too; faster means more | ENE4-010 evidence links speed to energy |
| 6 | How heat moves from hot to cold | ENE4-020, 021, 022, 023 | 4 | Heat always flows hot to cold; temperatures change as it flows; conductors and insulators; why metal feels cold | ENE4-023 why metal feels colder |
| 7 | What reaches your ears and your eyes | ENE4-030, 031, 032, 050, 051 | 5 | Faster vibration, higher pitch; stronger vibration, louder; you see a thing only when light from it reaches your eye; why the dark hides everything | ENE4-051 why the dark hides everything |
| 8 | How waves carry energy and messages | ENE4-040, 041, 042, 043, 044 | 5 | A wave carries energy, not water; amplitude and wavelength; draw it; a pattern can carry a message | ENE4-044 send a message with a pattern |
| 9 | How a circuit makes a bulb light | ENE4-060, 061, 062, 066 | 4 | The bulb lights only when the loop is complete; will it light; build one; electrical conductors and insulators | ENE4-066 the conductor / insulator sort |
| 10 | What a circuit gives out | ENE4-063, 064, 065 | 3 | Each part has a job; the current carries the energy; the circuit gives out light, heat, sound or motion | ENE4-065 what the circuit gives out |
| Design and build | |||||
| 11 | What a design must do, and what it must stay inside | SR4-020, 021, 022 | 3 | A job the design must do is a criterion; a limit it must stay inside is a constraint; write both down, then keep or cross out each idea against them (the demo of 2 October, adopted as built) | SR4-022 check the idea before you build |
| 12 | How to build and test an energy changer | ENE4-070, 071, 072, SR4-023 | 4 | Moving air or water can turn things; spot the energy change in a device; build an energy changer to a criterion and a constraint; test it against the rule with the same fair test for every design | SR4-023 test the design against the rule |
| Matter | |||||
| 13 | How to tell materials apart | MAT4-001, 002, 003 | 3 | Every piece of one material floats or sinks the same way; floater or sinker is a property of the material; pick out the sample that matches two properties | MAT4-003 the two-property pick |
| 14 | What mixtures and solutions are | MAT4-020, 021, 022, 023 | 4 | Mixed things are each still themselves; a solution is a mixture you cannot see the parts of; dissolved is not gone | MAT4-023 dissolved is not gone |
| 15 | Why the mass stays the same | MAT4-040, 041, 042 | 3 | Break a thing into pieces or mix two things and the total mass stays the same; predict the balance | MAT4-042 mix it, the mass holds |
| 16 | When a change makes a new material | MAT4-024, 060, 061 | 3 | Water frozen, melted or evaporated is still water; some changes make a new material; the clue is a changed characteristic | MAT4-061 the clue is a changed characteristic |
| Earth & Space | |||||
| 17 | What a rock is made of | EAR4-001, 002, 003 | 3 | Describe a rock by its grains and shine; rocks are made of minerals; test a mineral to tell it apart | EAR4-003 test a mineral |
| 18 | How igneous and sedimentary rock form | EAR4-007, 008, 009, 010 | 4 | Igneous rock: what it looks like, how melted rock cooled into it; sedimentary rock: what it looks like, how settled pieces pressed into it | EAR4-010 how sedimentary rock forms |
| 19 | The three rock families | EAR4-011, 012, 005, 006 | 4 | Metamorphic rock: what it looks like, how heat and squeezing changed it; sort a rock into its family; which rocks can hold water or oil | EAR4-005 sort a rock into its family |
| 20 | How rock breaks, moves and settles | EAR4-020, 021, 022, 023, 024, 025 | 6 | Weathering breaks rock in place; erosion carries the pieces; deposition drops them; what does each; then the sort | EAR4-025 weathering, erosion or deposition? |
| 21 | How rock layers tell the time | EAR4-035, 036, 037, 038 | 4 | Deeper is older; put layers in order; a fossil is as old as its layer; read the landscape's story | EAR4-038 read the landscape's story |
| 22 | What happens in an earthquake | EAR4-045, 046, 047 | 3 | Earth's rocky crust; the shaking spreads as waves (Topic 8); compare two defences | EAR4-047 compare two hazard defences |
| 23 | The water cycle | EAR4-053, 054, 055, 056, 057 | 5 | Water falls, gathers, evaporates and condenses in a loop; the Sun's energy drives it; predict the drop's next step | EAR4-057 predict the drop's next step |
| 24 | Where Earth's water is | EAR4-058, 059, 060, 061, 062 | 5 | Where Earth's water sits; why fresh water matters; the ocean feeds the cycle and connects all the water; build the model | EAR4-062 build the water cycle model |
| 25 | Weather and climate | EAR4-070, 071, SR4-010, 011, 012, EAR4-072 | 6 | Weather is today, climate is the usual pattern; make a bar graph of records; compare two places; one odd day does not change the climate; read the climate off the records | EAR4-072 work out the climate from records |
| 26 | How Earth's parts act on one another | EAR4-026, 080, 081 | 3 | Read Earth's features from a map; water, air, land and living things act on each other; spot the interaction | EAR4-081 spot the interaction |
| 27 | Energy from wind, water, sunlight and plants | EAR4-083, 084, 085, 086 | 4 | Four sources nature keeps giving | EAR4-086 plants as an energy resource (last of the four) |
| 28 | Fuels from under the ground | EAR4-087, 088, 089 | 3 | Coal, oil, natural gas: what each is and where it comes from | EAR4-089 natural gas (last of the three) |
| 29 | Which energy sources nature can replace | EAR4-090, 094, 091, 092, 093 | 5 | Renewable means nature keeps up; nonrenewable means it cannot; sort the seven sources; using any source leaves a mark; weigh one up | EAR4-093 weigh up an energy source |
| 30 | The Sun's path and the seasons | SPA4-001, 002, 003, 004 | 4 | The Sun's daily path; longer and shorter days through the year; read a season from its data; predict the next step (patterns only, no tilt) | SPA4-004 predict the next step in a seasonal pattern |
| 31 | The turning Earth and the stars | SPA4-007, 008, 005, 006, 009 | 5 | Earth spins once a day; a year is one orbit; star patterns keep their shapes; different stars in different seasons; the turning Earth moves the whole sky | SPA4-009 a turning Earth moves the whole sky |
| 32 | The Moon's changing shape | SPA4-020, 021, 022, 023, 024 | 5 | The shape seems to change; name the shapes; order them; predict the next; why it seems to change | SPA4-024 why the Moon's shape seems to change |
| Life | |||||
| 33 | Parts and their jobs, inside animals and plants | LIF4-001, 002, 003 | 3 | Match an internal part to its job; plant structures for tough places; from sense to brain to action | LIF4-003 from sense to brain to action |
| 34 | How plants make their own food | LIF4-010, 011, 012 | 3 | Plants make food from sunlight; animals cannot; trace the energy from the Sun to the eater | LIF4-012 trace the energy from the Sun |
| 35 | Producers, consumers and decomposers | LIF4-020, 021, 022, 025, 023, 024 | 6 | What each is; decomposers feed the soil; sort organisms by feeding role; read a food web ("the fox eats the rabbit", no predator or prey) | LIF4-024 read a food web |
| 36 | Traits from parents, and traits from life | LIF4-030, 034, 031, 032, 033 | 5 | Traits from parents, traits from life; sort them; when both play a part; instinct or learned behaviour | LIF4-033 instinct or learned |
| 37 | Life cycles of plants and animals | LIF4-040, 041, 042, 043, 044 | 5 | Pollination, seed forming, seeds travelling, germination; complete change or gradual growth in animal life cycles | LIF4-044 complete change or gradual growth |
| 38 | What happens when a place changes | LIF4-045, 050, 051, 052 | 4 | Seasons differ from place to place; fossils show past environments; some kinds have gone forever; adapt or go extinct | LIF4-052 adapt or go extinct |
Totals: 158 lessons, 38 practice sets, 38 PP100s (banks of at least 50 items each, at least 5 per atom), 4 strand-test placeholders (after Topics 10, 16, 32, 38), 1 end-of-grade test.
Why this grouping
- Every prerequisite edge points backwards in this order or into Grade 3. Checked atom by atom in the assembled files on 2 October (see "Checks run"); zero forward references.
- Topic 2 puts the fair test right where it is first needed (FOR4-004 requires SR4-003), so every later investigation in the year can call on it, including Topic 12's test of the design.
- Topic 12 needs Topic 4 (energy from giver to receiver, the carriers) for "spot the energy change", Topic 2 for the fair test, and Topic 11 for the criterion and constraint the build is tested against. After Physics is the earliest place all three hold.
- Topic 8 (waves) sits before Topic 22 (seismic waves need ENE4-040); Topic 21 (rock layers) sits before Topic 38 (reading past environments needs EAR4-036).
- The rock families are taught one family at a time, what it looks like then how it forms, and only then the sort (the 25 September ruling on the six per-family atoms). Topics 18 and 19 split them so no topic reaches seven.
- Energy resources follow Olivia's rule of surprising members first: wind, water, sunlight and plants (Topic 27) before the fuels everyone already calls "energy" (Topic 28), then the renewable-or-not sort on all seven (Topic 29).
- Topic 7 pairs sound and sight because both answer one question, "what has to reach you for you to hear or see?"; the two seeing atoms are too few for a topic of their own.
- No topic reaches seven lessons; none has fewer than three.
What changes: the folder gets grade4/topicNN_build/ per topic as each is built; Topic 11 is grade4/demo_criteria_constraints/ re-pointed as a topic folder (its code G4DEMO stays on the five live videos).
Card 3 — Scientific Reasoning is taught where it is used
The call: each of the 12 Scientific Reasoning atoms is a lesson inside the topic that first needs it, with its check there; no separate strand, no separate test.
| SR atom | Host topic | Why there |
|---|---|---|
| SR4-001 A question you can test; SR4-002 The one thing you change; SR4-003 Keep everything else the same; SR4-004 What you measure to see the result; SR4-005 Fair test or unfair test? | 2 How to run a fair test | the friction test (FOR4-004) is the first investigation of the year and requires SR4-003 |
| SR4-020 What counts as success; SR4-021 The limits you must work within; SR4-022 Design a solution | 11 What a design must do, and what it must stay inside | the design chain's first three steps, built and reviewed on 2 October as the demo |
| SR4-023 Test the design against the rule | 12 How to build and test an energy changer | the energy changer is the first real build; the fair test (Topic 2) is the test |
| SR4-010 Construct a bar graph; SR4-011 Compare two sets of results; SR4-012 The result that doesn't fit | 25 Weather and climate | monthly records make the first bar graph students build; two towns' records are the two sets; one freak day is the result that does not fit and does not change the climate |
Card 4 — Tests and benchmarks
The call: a PP100 per topic; a static end-of-strand test per strand except Design and build (placeholders until Becky's format gate is passed); one static end-of-grade test; all Grade 4 tests are our own banks, seeded from released grade-5 items filtered to Grade 4 atoms.
- No state tests science at grade 4 (D1 ruling). The released STAAR, Florida SSA and AZSCI grade-5 forms are cumulative over grades 3-5, so their items tagged to Grade 4 atoms seed the banks and set the style.
- Grade 4 content the grade-5 tests lean on hardest: the water cycle and the ocean (Topics 23-24, STAAR 5.10A builds on them), weathering-erosion-deposition (Topic 20, feeds STAAR 5.10C landforms), circuits (Topics 9-10, feeds 5.8B), mixtures and "the mass holds" (Topics 14-15, feed 5.6B and 5.6C), food webs and producers-consumers-decomposers (Topic 35, feeds 5.12B), the Moon's shapes and Earth's spin (Topics 31-32, feed 5.9A).
- The strand-test placeholders fall after Topics 10, 16, 32 and 38; the format is the Grade 3 proposal of 30 September (30 items, 27 to pass, three protected forms), unchanged until Becky rules.
- The end-of-grade test samples all four science strands plus Design and build, with free-response items.
Checks run (2 October 2026, re-run on the assembled files)
- Atoms placed: 158 = atoms in the Grade 4 registers (FOR4 10, ENE4 31, MAT4 13, EAR4 52, SPA4 14, LIF4 26, SR4 12). Every atom appears in exactly one topic; none is left over; none is doubled.
- Prerequisites: every prerequisite of every Grade 4 atom sits in an earlier topic of this plan, earlier in the same topic, or in Grade 3. Zero violations (script output in
grade4/records/ARCHITECTURE_CHECK_2026-10-02.txt). - Titles: every topic title fits "Here's everything we found out about ___".
- Topics of 7+: none. Topics of 2 or fewer: none.
What happens next
Topic 1 ("Why sliding things stop") gets its blueprint in the Grade 3 shape, then its lessons, quizzes, summary, practice, PP100 bank and scripts, straight through; the Grade 3 Forces golden pack is checked for reuse (FOR3-003's "a push or pull can slow or stop things" is friction's doorway). Topics follow in order. A lesson whose best teaching is genuinely uncertain comes to James as one question on the topic's decisions page; nothing else waits.