Topic 19 — Sinks, floats, sticks to a magnet: choosing materials — blueprint (28 September 2026)
What I need from you: 2 decisions
May L02 offer "attracts" once, at its close, as the test papers' word for what the magnet does?
Topic 4 taught "a magnet pulls steel" and never said "attract". The STAAR, Florida and Arizona papers say "attracted to a magnet". L02 keeps "pulls" in every frame, chip and option and says, as its last line after the return: "When a magnet pulls an object, we also say the magnet attracts it." The word then sits in the glossary and nowhere else (the reviewer's and coordinator's call: one sentence does not earn a recall item, so the practice term item was cut).
My recommendation: keep the one line, so the test word is met once before the exit tests.
Does the type sheet stand — ten types, the hard tier typed, every exemplar a fresh instance?
the non-author review found four exemplars that were lesson checks renamed; all ten were re-read against every lesson case, quiz item, practice item and the intro and re-instanced where needed (the table on the type sheet). PP-9 accepts "clear" as well as "see-through" — the everyday word a child writes for a property the lesson taught as "see-through".
My recommendation: approve; keep "clear" in PP-9's accept list.
Topic 19 at a glance — 4 lessons
| Lesson | Opens on | Format | |
|---|---|---|---|
| L01 | Does it sink or float? | Here is a big wooden log and a small steel nail. | video + article |
| L02 | Does a magnet pull it? Sort them | Here are two paperclips. | video + article |
| L03 | Mix two materials to do a job | Yoel wants to make a brick. | video + article |
| L04 | Say why that material | Effie runs across the kitchen floor in her socks. | video + article |
What this topic is, in five lines
Four short lessons, one per atom, in the Matter strand after Topic 18's comparisons. L01 and L02 are two property TESTS a child can run and record: does it sink or float (lower it in, let go, write it down), does a magnet pull it (bring a magnet close, sort into two groups). L03 is a routine: make each material alone and the two mixed, the same way, test them the same way, and see which does the job best (sand, clay, and sand and clay; then flour, water and dough). L04 is the justification: to say why a material suits a job, name the property the job needs and say the material has it (rubber for a grippy sole; glass for a see-through window; plastic for a raincoat; cotton for a pillow), with a non-example at each boundary (a glass sole; a paper raincoat).
The surprising cases open L01 (vault pattern: teach the surprising members first): a big wooden log floats and a small steel nail sinks, so "big things sink" never forms; the payoff is "you cannot tell by looking, you test it". L02 opens on two paperclips of the same shape, so the shape cannot be the sort and the test has to be. L02 coins "material" ("the stuff an object is made of"); everything else is an earlier topic's word (property, Topic 16; fair test, Topic 7; magnet and steel, Topic 4).
Topic 4's bar magnet, paperclip, nail and two cans are imported, not redrawn; Topic 17's shared helpers draw the rest. The tank, the results table, the two groups and the three bricks are this topic's new register entries (content/figures.py).
Applied without asking (rulings you have already given): hard PP100 items are typed (three of ten exemplars, all text entry, accept lists generated); every attached question stands alone with its own drawing on the video's own scene and never prints the key's word; no option bundles a verdict with a reason; every stem a positive question; colour in figures; scene changes spoken with "let's" in the intro and never as an imperative; the intro ends on a ready line and a poll and names no lesson; three questions on the summary; sinking and floating is a TEST recorded, never explained ("density" is not said); the surprising members first (the big log floats, the small nail sinks); the magnet PULLS steel, never cutlery as the steel example; "stuff" beside the coinage of material; nothing is "weighed", "heavier" or "lifted"; scripts under 150 words; quiz of about ten; no sub-agents beyond the one cold reader.
Does it sink or float? L01
Here is a big wooden log and a small steel nail.
Fidel has a tank of water.
He says the log will sink, because it's so big.
He says the nail will float, because it's so small.
Is Fidel right?
How could you find out for sure?
Lower the object into the water and let go.
If it goes to the bottom, it sinks.
If it stays at the top, it floats.
The big log floats, and the small nail sinks.
You cannot tell by looking.
You test it, and you write down what happened.
Video: the log lowering and settling at the waterline; the nail dropping to the floor; the candle stub settling mostly under; the table filling row by row — video and article.
Part 1 — MAT3-007 — Test whether an object sinks or floats and record it: lower it in, let go, watch where it ends up, write one row per object
Part 1q — quiz, 13 items
Does a magnet pull it? Sort them L02
Here are two paperclips.
They are the same shape and the same size.
One is steel and one is plastic.
Tomi holds a magnet just above each one.
Which paperclip will the magnet pull?
The magnet comes close, and the steel paperclip jumps up to it.
The plastic paperclip stays where it is.
The two paperclips look the same, but the test tells them apart.
The stuff an object is made of is called its material.
Bring a magnet close to each object, and sort by what happens.
Video: the steel clip jumping to the magnet while the plastic one stays; the objects sliding into their two boxes — video and article.
Part 1 — MAT3-008 — Sort materials into those a magnet pulls and those it does not, by testing each one; coin material
Part 1q — quiz, 12 items
Mix two materials to do a job L03
Yoel wants to make a brick.
He presses wet sand into a block and leaves it in the sun to dry.
When the block is dry, he presses on it.
It falls to bits.
What could he add to the sand to make a brick that holds together?
Yoel makes three bricks the same size: sand only, clay only, and sand and clay mixed.
He dries them the same way and presses on each with the same push.
Only what the bricks are made of is different, so it is a fair test.
The sand brick falls to bits, the clay brick cracks, and the mixed brick stays whole.
Two materials mixed together can do a job better than either one alone.
Video: the sand block collapsing to a heap; the three push arrows; each brick changing on its word — video and article.
Part 1 — MAT3-060 — Mix two materials so the result does a job better than either alone, and show it with a fair test (three bricks the same size, the same drying, the same push)
Part 1q — quiz, 11 items
Say why that material L04
Effie runs across the kitchen floor in her socks.
She slips and nearly falls.
She puts on her sneakers and runs again.
Now she does not slip.
The sneakers have rubber soles.
Why does rubber do the job?
A sole has a job: to grip the floor.
So the job needs a material that is grippy.
Rubber is grippy, so rubber suits a sole.
Glass is smooth and slippery, so glass does not suit a sole.
To say why a material suits a job, name the property the job needs, and say the material has it.
Video: Effie sliding, then running steadily in sneakers; the two soles with their tick and cross; the rain running off the plastic coat and soaking the paper one — video and article.
Part 1 — MAT3-061 — Say why a material suits a job by naming the property the job needs and saying the material has it; a non-example at each boundary
Part 1q — quiz, 11 items
Language decisions
- The atoms' words: "sinks" and "floats" (MAT3-007, everyday words, not coined), "pulls" (MAT3-008, Topic 4's verb; "attracts" once — decision 1), "mixed together" for MAT3-060's "combine", "suits" for MAT3-061's "justify a choice". Coined here: material ("the stuff an object is made of"). Earlier topics' words reused, never re-coined: property (Topic 16), fair test (Topic 7), magnet and steel (Topic 4), aluminum (Topic 4).
- Sinking and floating is recorded, never explained. "Density", "heavy", "heavier", "weighs" and "light" (for mass) do not appear; the surprising pair is described by size only ("the big log", "the small nail").
- Never cutlery as the steel example (James): the steel things are a paperclip, a nail, a can, a bolt, a screw, a bottle cap, a thumbtack, a key ring.
- Openers vary: L01 "Here's a big wooden log…", L02 "Here are two paperclips.", L03 "Yoel wants to make a brick.", L04 "Effie runs across the kitchen floor…"; scripts open on the scene, no title slide; contractions in scripts and headaches.
PP100 type sheet (TYPE_SHEET_ONLY; James's 28 Sep night ruling: hard items are typed)
Ten types, ten exemplars, every one a fresh instance (re-read after the non-author review), at most two alone-types per atom; easy and medium are four-option MCQs, the three hard types are text entry with generated accept lists. Coverage table in records/TYPES_G3T19.md.
Figures
63 figures; every drawing a verdict is read from is SVG (tanks, magnet tests, the two groups, the three bricks, every table); five photos (the log and nail; the two paperclips; a brick; a rubber sole; a glass window); one cartoon (Effie sliding in her socks). Every figure has an IMAGE_BRIEFS entry and an IMAGE_KINDS entry; people and hands are never drawn as glyphs (the magnet is held by nothing drawn). Item figures carry the objects' names and no verdict chip; the blind comment gives the place, the hanging or resting, the table's cells, never the verdict word.
Deliberately not taught
Why things sink or float (density: Grade 4's heavy-for-its-size atom); whether the same material always sinks (MAT4 re-enters sink/float as a property of the material — L01 tests objects); any object that hovers or sinks slowly; why a magnet pulls steel (Grade 4); "combine" and "mixture" as words (Grade 4 mixtures, MAT4 SD-2); more than one thing changed in a test; any property the job needs that the course has not named (strong, stretchy) — the four properties in L04 are grippy, see-through, keeps water out, soft, plus floats and a-magnet-pulls-it from L01 and L02.
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.