Topic 34 — Backbone or no backbone — blueprint (29 September 2026)
What I need from you: 4 decisions
Do we say, in so many words, that people are animals?
the common finding for this age is "humans are not animals". L02 puts the student in the vertebrate group by touch ("Feel down the middle of your own back… You have a backbone too.") and L03 says "Your own leg bends at the knee and the ankle. Those are joints too." Neither sentence says "people are animals". No LIF3 atom defines "animal"; Topics 32 and 33 use the word plainly.
My recommendation: keep the touch line, add no claim about people being animals until an atom carries it (proposal LIF3-P01 in records/ATOM_PROPOSALS_G3T34.md).
Does the arthropod table's first question read "No backbone?" with a tick, or "A backbone?" with a cross?
the atom's three features are worded "no backbone, a hard outer casing, jointed legs", so the three-question card asks "No backbone?" and an arthropod's row is three ticks (yes to all three — the same shape as Topic 32's four-yes sort). The cost is one line of reading: a tick under "No backbone?" means "yes, it has none". L03 says this once on the crab. The alternative, "A backbone?" with a cross, breaks the three-yes shape.
My recommendation: keep "No backbone?" — one shape for "yes to all" across the strand.
Is the turtle the right second appearance?
the turtle is L02's boundary case (hard shell outside, backbone inside — its backbone is joined to the shell) and L03's first non-example (hard outside, jointed legs, but a backbone). One photo key, two lessons; L03 opens its turtle section with "You've already seen that it has a backbone." Topic 35 will place the turtle among the reptiles.
My recommendation: keep — the same animal failing the arthropod check on the ONE feature L02 taught is the cleanest boundary the topic has.
Do the nine question types stand?
nine types (three easy MCQs, four medium MCQs, two typed hard), coverage alone and in pairs, in records/TYPES_G3T34.md (rendered course_preview/review/TYPES_G3T34.html).
Topic 34 at a glance — 3 lessons
| Lesson | Opens on | Format | |
|---|---|---|---|
| L01 | Make a group from one shared feature | Jethro and Kerensa each have the same six animal cards: a lion, a bear, a parrot, an owl, a snake, a lizard. | video + article |
| L02 | Backbone or no backbone | A visitor brings a snake to Mirren's class. | video + article |
| L03 | What makes an animal an arthropod | Inigo crouches at a rock pool. | video + article |
What this topic is, in five lines
Three short lessons, one per atom, the third topic of the Life strand. L01 teaches what a feature is (something you can see on an animal's own body) and how ONE feature makes a group: Jethro and Kerensa sort the same six animal cards and get different piles, and both are right, because each picked a feature — Topic 16's criterion carried over (once the feature is picked, there is one right way; where an animal lives, and who likes it, are not features). L02 sorts animals by the backbone, surprising members first: the visiting snake Mirren says has no bones (the X-ray shows a line of many small bones), the worm with nothing inside, the fish, the cat, the turtle (hard shell outside, backbone inside) and the crab (hard shell outside, no bones inside) — coining backbone, vertebrate and invertebrate. L03 gives the arthropod's three features as a three-question check on the crab, the spider and the beetle, with the turtle (a backbone) and the snail (no legs) as the two one-no non-examples.
The sort tables are Topic 32's look (the question as the column header, a green tick or red cross under it, a verdict chip). Real animals are photographs — the strongest case in the course for photos (a snake X-ray; a crab's legs close up). Children and story scenes are cartoons the pipeline draws.
Applied without asking (rulings you have already given): hard PP100 items are typed (two of nine exemplars); every attached question stands alone with its own drawing; no option bundles a verdict with a reason; claim items are bare yes / no; every stem a positive question; colour in figures; scene changes spoken with "let's" and never as an imperative; the intro ends on a ready line and a poll and names no lesson; three questions on the summary; surprising members first (the snake and the fish have a backbone; the worm has none; a crab is an arthropod); a claim-maker is used once per topic; a headache character never appears in an item; a verdict mark sits under its drawn question; one lesson per atom, three lessons; nothing said about insects (no atom asks); the five vertebrate groups left to Topic 35.
Make a group from one shared feature L01
Jethro and Kerensa each have the same six animal cards: a lion, a bear, a parrot, an owl, a snake, a lizard.
'Put the cards into groups,' says their teacher.
Jethro makes three piles.
Kerensa makes two.
Their piles don't match.
Who did it right?
Something you can see on an animal's own body, like fur, feathers or legs, is called a feature.
Jethro picks one feature, fur, and asks every card the same question: does it have fur?
The lion and the bear go in.
The other four stay out.
Kerensa picks a different feature, wings, so she gets different groups.
Both picked a feature, so both were right.
Video: the ticks and crosses landing under each card as it is named; the cards sliding into their boxes; the same cards regrouping by wings — video and article.
Part 1 — LIF3-010 — Group a set of animals by a feature they share
Part 1q — quiz, 11 items
Backbone or no backbone L02
A visitor brings a snake to Mirren's class.
It winds round the visitor's arm, bending into curve after curve.
'It has no bones,' Mirren says.
'It's soft all the way through, like a worm.'
Is Mirren right?
An X-ray of the snake shows a line of many small bones down its whole length.
A line of bones down the middle of the back, inside the body, is called a backbone.
An animal with a backbone is called a vertebrate.
An animal with no backbone is called an invertebrate.
The turtle has a hard shell outside and a backbone inside.
The crab has a hard shell outside and no bones inside.
A hard shell on the outside is not a backbone.
Video: the line of bones glowing along the X-ray; the sort table filling row by row; the turtle then the crab with the chip A SHELL IS NOT A BACKBONE — video and article.
Part 1 — LIF3-011 — Sort animals into those with a backbone (vertebrates) and those without (invertebrates)
Part 1q — quiz, 12 items
What makes an animal an arthropod L03
Inigo crouches at a rock pool.
A crab scuttles sideways over the rocks.
At home that evening, a spider hangs in the corner of his room, and a beetle crawls across the step.
A crab, a spider and a beetle look nothing alike.
But scientists put all three in one group.
What do they share?
A crab's leg is made of hard pieces that bend only at the joints: a jointed leg.
A hard covering on the outside of the body is called a hard outer casing.
The crab has no backbone, a hard outer casing and jointed legs.
An animal with all three features is called an arthropod.
The turtle has a backbone, so it is not an arthropod.
The snail has no legs, so it is not an arthropod.
Video: the drawn leg bending at its two joints; the three-question card; the crab's row filling tick by tick; the turtle's cross under No backbone? and the snail's under Jointed legs? — video and article.
Part 1 — LIF3-070 — State what makes an animal an arthropod: no backbone, a hard outer casing, jointed legs
Part 1q — quiz, 11 items
Language decisions
- "feature" — something you can see on an animal's own body (fur, feathers, scales, legs, wings). Topic 16's "property" stays with objects; its two boundaries carry over (where it is; who likes it).
- "backbone" — a line of bones down the middle of the back, inside the body. "vertebrate" / "invertebrate" — the 'in' at the front means no. Not said: "spine", "skeleton", "vertebra", "bug", "shellfish", "exoskeleton", "insect".
- "arthropod" — an animal with no backbone, a hard outer casing and jointed legs; "joint" — a place where a leg bends; "jointed leg"; "hard outer casing" — a hard covering on the outside of the body (the atom's words).
- An X-ray picture "shows the bones inside a body" — one plain line, not coined.
- Openers vary: "Jethro and Kerensa each have…", "A visitor brings a snake…", "Inigo crouches at a rock pool."; contractions in scripts and headaches; scene changes with "Now consider…", "Now let's…".
PP100 type sheet (TYPE_SHEET_ONLY; James's 28 Sep night ruling: hard items are typed)
Nine types, nine exemplars, at most two alone-types per atom; seven four-option MCQs (easy and medium) and two typed hard items (the group named from the feature's description; the missing arthropod feature). Coverage table in records/TYPES_G3T34.md.
Figures
54 figures: 20 svg (the cards, the group boxes, the not-a-feature card, the two sort tables in their growing states, the backbone diagram, the three-question card, the jointed-leg diagram, three rule cards), 30 photos (every real animal, the two X-rays, the turtle skeleton), 4 cartoons (Jethro and Kerensa's cards; Mirren and the visiting snake; Inigo at the rock pool; Tallis in the aquarium tunnel). Every figure has an IMAGE_BRIEFS and an IMAGE_KINDS entry; people and hands are never drawn as glyphs; every verdict mark sits under its drawn question.
Deliberately not taught
What an animal is (no atom; proposal LIF3-P01); the five vertebrate groups (Topic 35, LIF3-015…019, 012); insects as a group inside the arthropods (no atom asks — the beetle, spider and crab are named as arthropods only); why a hard outer casing must be shed to grow; the bones' names; that a turtle's shell is made of bone (one line says its backbone is joined to the shell); plants grouped by features (LIF3-014, seeds and spores, Topic 37); "shellfish" and "bug" as words.
This grade’s course architecture — open only if you want the whole map
Skill: course-build → atomise (architecture, step 6b gate) → write-like-james @ acc4fb6
Grade 3 Science — course architecture v3 (James's rulings of 25 September, plus Olivia Mullins's sequencing)
Read this in five minutes. Grade 3 Science is ONE course with a fixed order; nobody picks strands. It arranges the 183 Grade 3 atoms into four strands and forty-two small topics, each with its own mixed practice, summary video and PP100. Nothing below writes a lesson sentence. The atoms stay where they are: the Science Knowledge Graph's 3-5 registers.
Rulings recorded (James, 25 September 2026)
- Strand order: Physics, Matter, Earth & Space, Life. James: "I don't think it matters hugely … Happy to go with 1 Physics 2 Matter 3 Earth and space 4 Life. That works well." Strands may be intermingled later if a reason appears; none does yet.
- Grade 3 is one course. "We're not going to allow students to pick any strand … we need to structure Grade 3 as we think Grade 3 should be structured best." v1's line about students choosing strands was wrong and is gone.
- Topic 1 is the pilot. "That topic 1, I think, works as a good pilot."
- Small topics. "3 atoms is fine for testing. PP100s on quite granular stuff is absolutely fine … A 4-atom topic and a 5-atom topic is great. 9 is too many, really … if something's got 9 atoms, we should be considering splitting it." So sound, soil, fossils and natural resources each stand alone, and every v1 topic of nine or more was split (Card 2). Topics 1 and 2 keep 8 and 7 lessons because James approved Topic 1 as it stands and Topic 2 is one chain about speed; both are flagged as split candidates once their PP100 data arrives.
- Forces opens with Earth's pull and magnets, before the word "force" (Olivia Mullins call, 25 September; James: "I think I'll follow that"). Topics 3 and 4 teach the two non-touching pulls with no talk of forces; Topic 5 coins "force" on both of them and on the hand push together, so the hand push never becomes the whole category. Her two classroom misconceptions (Earth pulls only on your feet; "balanced" is a kind of force) are in the register and the lessons.
- States of matter start with air (Olivia): air takes up space → gases spread → liquids → solids → the sort.
Applied from the earlier rulings: four strands; Motion before Forces before Energy; Scientific Reasoning atoms taught inside the topics that use them; one intro video per strand and per topic, each teaching nothing; one atom, one lesson, both video and article; a summary video before every PP100; PP100 banks of at least fifty items tagged by depth of reasoning; the Forces topics reuse the golden pack; the language rules (Earth's pull, carriers not forms, no "leak" or "lift").
Card 1 — The strands and their order
The call: Physics → Matter → Earth & Space → Life, each with its own intro video and its own end-of-strand test.
| Strand | Topics | Atoms | Why it sits here |
|---|---|---|---|
| Physics | 1-15 | 64 | Motion first: what you can see, before the invisible cause. Energy last: "faster means more energy" needs speed. |
| Matter | 16-21 | 22 (+7 Scientific Reasoning) | Uses the measuring tools and feeds Earth's water cycle in Grade 4. |
| Earth & Space | 22-31 | 41 (+4 Scientific Reasoning) | Weather uses tables and graphs; "the Sun powers Earth" must precede food chains. |
| Life | 32-42 | 43 | Ends the year; leans on Space (the Sun), Forces (Earth's pull) and Matter (properties). |
Scientific Reasoning's 13 atoms are spread through Topics 1, 16, 17, 22, 23 and 25 (Card 4). Total 183 lessons.
Card 2 — The topics
The call: forty-two topics, most of three to six lessons; a mixed mastery practice set, a summary video and a PP100 at the end of every one.
| # | Topic (student-facing title) | Atoms (in teaching order) | Lessons | The big idea it serves |
|---|---|---|---|---|
| Physics | ||||
| 1 | Where is it? Did it move? | MOT3-001, 002, 003, 004, 005, 006, 007, 008 (+ SR3-020, 021 inside L07/L08) | 8 | You say where something is with a landmark; moving means its position changed; motions can repeat |
| 2 | Fast and slow | MOT3-020, 021, 022, 023, 024, 025, 026 | 7 | Faster means farther in the same time, or the same distance in less time |
| 3 | Earth pulls things down | FOR3-021, 029, 030, 028, 022 (+ a closing lesson naming gravity) | 6 | Earth pulls every object, all the time, straight down, on every part of it, without touching; a strong enough pull can beat it; the pull's name is gravity (JM 28 Sep 2026; no word "force" yet) |
| 4 | Magnets | FOR3-023, 024, 025 | 3 | A magnet pulls steel without touching; two magnets pull or push; use a magnet to solve a problem (no word "force" yet) |
| 5 | What a force is | FOR3-012, 001, 008, 006 | 4 | Earth's pull, a magnet's pull and your push are all forces; push or pull; on one object; in one direction |
| 6 | Forces that touch, and forces that don't | FOR3-020, 027, 026 | 3 | Some forces act without touching: Earth, magnets, a rubbed balloon; most pushes touch |
| 7 | Pushes and pulls change things | FOR3-002, 003, 004, 005, 007 | 5 | A push or pull starts, stops, turns or squashes; you can test it |
| 8 | Strong or weak: drawing a force | FOR3-009, 010, 011 | 3 | A stronger push makes a bigger change; an arrow shows a force's direction and strength |
| 9 | Balanced forces | FOR3-040, 041, 042, 043, 045 | 5 | Several forces act at once; balanced forces leave motion as it is, still or steady |
| 10 | Unbalanced forces | FOR3-044, 046, 047 | 3 | Unbalanced forces speed up, slow down or turn |
| 11 | Energy: what has it, how it travels | ENE3-001, 002, 003, 004, 005, 034 | 6 | Energy makes things happen; light, sound and electricity carry it; faster means more |
| 12 | Sound | ENE3-030, 031, 032 | 3 | Sound comes from vibration and travels to your ear |
| 13 | Light: sources, straight lines, shadows | ENE3-010, 011, 012, 017 | 4 | Light comes from a source, travels straight, makes shadows, must reach the eye |
| 14 | Light bounces, bends or soaks in | ENE3-013, 014, 015, 016 | 4 | Reflection, refraction, absorption, sorted |
| 15 | Light and heat | ENE3-020, 021, 033 | 3 | Light-givers give heat; rubbing makes heat; light carries energy |
| Matter | ||||
| 16 | Describe it, sort it | SR3-001, 002, MAT3-001, 002, 003 | 5 | Observe with more than your eyes; describe an object by its properties; sort and order |
| 17 | Measuring tools | SR3-003, 004, 005, 006, 007 | 5 | Thermometer, scale, measuring jug; pick the right one; two groups can disagree |
| 18 | Which has more? | MAT3-004, 062, 005, 006 | 4 | More mass, more space, warmer, decided by a measurement; MAT3-062 "everything takes up space" (JM ruling on Olivia's comment, 28 Sep 2026) sits before the space comparison |
| 19 | Sinks, floats, sticks to a magnet: choosing materials | MAT3-007, 008, 060, 061 | 4 | Test a property, then pick the material for the job |
| 20 | Solids, liquids and gases | MAT3-063, 064, 065, 022, 023, 021, 020, 024 | 8 | Air first (Olivia's order): air is something you can feel; it is made of tiny pieces too small to see; so is every kind of matter; air takes up space; gases spread out to fill their space; liquids take their container's shape; solids keep theirs; then the sort with the awkward cases. MAT3-063, 064, 065 were added on 28 Sep 2026 (JM's rulings on Olivia's comments) before MAT3-022 in the chain; eight lessons is over JM's 3–6 size, so the Topic 20 build record (decision 1) proposes a split after MAT3-022 into "Air is something" (4) and "Solids, liquids and gases" (4), renumbering Matter to 16–22, Earth & Space 23–32, Life 33–43 — nothing after Topic 19 is authored, so the renumbering costs nothing now |
| 21 | Heating and cooling | MAT3-040, 041, 042, 043, 044, 045, 046 | 7 | Heating and cooling change the state but it is the same water (split candidate: melting/freezing vs evaporating/condensing) |
| Earth & Space | ||||
| 22 | Measuring the weather | EAR3-017, 018, 019, SR3-010, EAR3-020, SR3-011 | 6 | Three instruments, a weather diary, reading it back |
| 23 | Weather over a season, and far away | SR3-012, EAR3-022, 023, 021, 024 | 5 | A season's records make a chart; the chart predicts; other places differ |
| 24 | Volcanoes, earthquakes, landslides | EAR3-007, 010, 008, 011, 009, 012 | 6 | What each one is, then how it changes the land fast |
| 25 | Dangerous weather | EAR3-013, 014, SR3-022 | 3 | Weather can do damage; a defence holds it back; pick the sensible cause |
| 26 | Soil | EAR3-001, 002, 003, 004 | 4 | Soil is broken rock plus dead things |
| 27 | Fossils | EAR3-029, 030, 031, 032, 033 | 5 | A few dead things last as fossils and tell of the past |
| 28 | Using and conserving natural resources | EAR3-040, 041, 042, 043 | 4 | Everything you own started as a natural resource; some run short |
| 29 | The Sun | SPA3-001, 007, 002 | 3 | A huge glowing ball of gas; a star; the source of Earth's energy |
| 30 | The stars | SPA3-003, 004, 005, 006 | 4 | Stars differ; they look like dots because they are far; telescopes show more |
| 31 | The solar system | SPA3-010, 011, 012, 013, 014 | 5 | Earth orbits the Sun with seven other planets; the Moon orbits Earth |
| Life | ||||
| 32 | Alive or not | LIF3-001, 007, 008, 009, 002 | 5 | Living things grow, feed, move and make more; sort living from non-living |
| 33 | What living things need | LIF3-003, 004, 005, 006 | 4 | Food, water, air and a place that suits them |
| 34 | Backbone or no backbone | LIF3-010, 011, 070 | 3 | Grouping by shared features; vertebrates, invertebrates, arthropods |
| 35 | The five vertebrate groups | LIF3-015, 016, 017, 018, 019, 012 | 6 | Mammal, bird, reptile, amphibian, fish, then the sort |
| 36 | Eggs, body parts and senses | LIF3-013, 020, 027 | 3 | Egg-layers or live birth; body parts do survival jobs; animals sense, then respond |
| 37 | How plants make new plants | LIF3-071, 072, 014, 024 | 4 | Seeds, spores, the sort, the flower's job |
| 38 | Plant parts and their jobs | LIF3-021, 022, 023 | 3 | Roots, stem, leaves |
| 39 | Plants respond | LIF3-025, 026, 028 | 3 | Stems grow to the light, roots grow down; plants respond by growing, animals by moving |
| 40 | Life cycles and family likeness | LIF3-030, 031, 040, 041, 042 | 5 | Every life runs in a cycle; offspring take after their parents but differ |
| 41 | Food chains | LIF3-050, 051, 052 | 3 | Every food chain starts with the Sun; remove a link and the rest changes |
| 42 | Living together and coping with change | LIF3-060, 061, 062, 063 | 4 | Groups, places and seasons decide who survives |
Totals: 183 lessons, 42 practice sets, 42 PP100s (banks of at least 50 items each), 4 strand tests (after Topics 15, 21, 31, 42), 1 end-of-grade test.
Why this grouping
- Every prerequisite edge points backwards in this order. Checked atom by atom in the assembled files; no forward reference.
- Animal topics (33-35) and plant topics (36-38) are separate, as James asked; the plant-versus-animal response contrast (LIF3-028) closes Topic 38 because it needs both sides taught.
- Topics 3 and 4 teach Earth's pull and magnets without the word force; Topic 5 coins it on all three kinds (Olivia's sequence). Topic 8 carries the two force-arrow atoms so Topics 9 and 10 can draw balanced and unbalanced forces.
- Topic 24 puts "what a volcano is" straight before "volcanoes change the land fast", and the same for earthquakes and landslides: what it is, then what it does.
What changes: the folder gets grade3/topicNN_build/ per topic; Topic 1's blueprint is approved; Topic 1 is built first.
Card 3 — Topic 1 is the pilot (approved)
The call: pilot "Where is it? Did it move?" end to end — 8 lessons, an attached question per video, a ten-item quiz after each, mixed practice, summary video, PP100 — before any other topic starts.
- It is the first thing a Grade 3 student meets, so the whole format ladder gets tried where the stakes are lowest.
- It holds a fact, four sorts, two routines and a prediction. Every check type the course needs appears once.
- Its quiz items are drawings of everyday scenes, so the figure pipeline for young grades gets tested too.
- Topics 3 to 10 follow, reusing the golden Forces pack where its lessons match (push or pull, force on one object, strength, direction, more than one force, the balanced and unbalanced lessons).
Card 4 — Scientific Reasoning is taught where it is used
The call: each of the 13 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 |
|---|---|---|
| SR3-001 Observe with more than your eyes; SR3-002 Observation or idea about it? | 16 Describe it, sort it | describing an object's properties is observing |
| SR3-003 Read a thermometer; SR3-004 Measure mass with a scale; SR3-005 Measure the volume of a liquid; SR3-006 Pick the right measuring tool; SR3-007 Two groups, two different answers | 17 Measuring tools | the tools before "which has more?" uses them |
| SR3-010 Record results in a table; SR3-011 Find a value in a table | 22 Measuring the weather | the weather diary is the first table students fill and read back |
| SR3-012 Read a pictograph or bar graph | 23 Weather over a season | the graph before the graphing routine |
| SR3-020 Spot the pattern; SR3-021 Use the pattern to predict | 1 Where is it? Did it move? (inside L07 and L08) | the swing's repeat is the pattern |
| SR3-022 Choose the sensible cause | 25 Dangerous weather | first place students pick a cause for an event |
Card 5 — Tests and benchmarks
The call: a PP100 per topic; a static end-of-strand test per strand (some free response); one static end-of-grade test; all Grade 3 tests are our own banks, seeded from released grade-5 items filtered to Grade 3 atoms.
- No state tests science before grade 5 (D1 ruling). The released STAAR, Florida SSA and AZSCI grade-5 forms give the style and difficulty; items tagged to Grade 3 atoms seed the banks.
- The strand tests fall after Topics 15, 21, 31 and 42.
- The end-of-grade test samples all four strands with free-response items.
What happens next
Topic 1 is built as the first interactive version for James: the topic intro (video script and article), eight lessons each as a video script with animation guidance and an article with figures, one attached question per video, a ten-item quiz per lesson, mixed practice, the summary video script and the PP100 bank. Topic 3 follows, reusing the golden pack.