Tracking science kits, programs, and curriculum that are shallow by design (or default) - and those that go deep.
Science Ed Ledger
The Science Ed Ledger tracks K–8 science curricula across several publishers. What they teach, how they teach it, whether the foundational science holds up. We score every unit on the What-Why Gap, Mapping Errors, and Factual Errors. Updated as we evaluate new programs.
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New here? We measure three problems in science curricula: the What-Why Gap (asking students to explain before teaching them the causal pieces), Mapping Errors (language that points toward ideas science left behind), and Factual Errors (statements that are scientifically wrong - Not Recommended).
Why this matters →
ACS Chapter 1 (Grade 2, Lessons 1.1–1.4) is the NGSS-aligned K-2 unit on observable properties of materials. Excellent fair-test inquiry, real engineering integration, zero map errors, 78.6% green practices. Not Recommended verdict (Foundation 21.7%) because only one passage in the whole unit names "water molecules" - NGSS 2-PS1 defers atoms to grade 5.
ACS Lesson 2.1 (Grade 2) - the second ACS unit reviewed. Same publisher and same NGSS standard as Ch 1 (Not Recommended, 21.7%), but the EXPLAIN section is built around 5 molecular passages: water/oil/glucose molecules each explained for size, shape, and adhesion. Foundation 100%, Recommended, deep tier. A 78-point gap from Ch 1 driven by lesson architecture, not by content correctness.
ACS Lesson 3.1 - strongest ACS lesson. Same NGSS standard as Ch 1 (Not Recommended) but builds EXTEND around 5 molecular passages explaining why water dissolves Skittle sugar but not M&M chocolate (hydrophilic vs hydrophobic). First ACS lesson to name atoms ("water = 3 atoms"). Foundation 100%, Practices 78.6% green. One FSE flagged (Skittle pectin → handled as editorial errata only).
ACS Lesson 4.1 (Grade 2 Float and Sink) - a lean ACS lesson. Density formula explicitly deferred, zero molecular content. Excellent fair-test inquiry and a memorable three-layer liquid demo, zero map errors. But Foundation 0% (Not Recommended, floor) because there's no atomic anchoring anywhere. Most extreme Type 6 Clean-but-Empty case.
ACS Chapter 5 unit (Lessons 5.1+5.2). Foundation 91.3%, Recommended deep. 5.1's molecular kinetic theory in the objective scaffolds 5.2's chemical-change content. 5.1 has explicit control group; 5.2 has student-led fair-test design. Both align to NGSS 2-PS1-4 (argument with evidence). Practices 85.7% green. Only 2 passages UNSCAFFOLDED (chemical-reaction concept needs atomic explanation).
ACS Chapter 6 (6.1+6.2). Foundation 100%, Recommended deep. THE atoms-first chapter - explicitly exceeds NGSS to add atomic framing. Six molecules built from named atoms (H₂O, CO₂, NH₃, CH₄, H₂O₂, acetic acid). Color-coded Snap Cubes match professional chemistry conventions.
BFSU's first K-2 matter lesson - introduces solid/liquid/gas via a Sorting Game with three boxes plus ice-melting and water-boiling observations. Zero map errors. Foundation 0% because atoms, molecules, and even "particle" don't appear - by design, since particulate nature is deferred to Lesson A-4.
BFSU K-2 foundational lesson establishing air is a real substance. Hands-on balloon-balance and inverted-cup demos. Four-spheres model. Zero map errors - clean BFSU lesson. Foundation 10% (high for BFSU) because the gap is 90% - "atom" and "molecule" don't appear, only generic "particles."
K-2 lesson on energy. Substance model taught by design - author defends it explicitly: there is no way of defining energy beyond recognizing it as heat, light, electricity, or motion. Battery as bottle of water, heat moves, light flows, energy travels downhill. Foundation 0%, gap 97.4%, 18 map errors (16 REI-substance + 2 AEC).
The first BFSU lesson to clear the Not Recommended threshold. Sound is grounded in vibration (frequency↔pitch, amplitude↔loudness) and transmitted via air particles bumping each other (referencing A-4). Lesson explicitly invites students to debate whether sound is "unique energy" or "movement energy." Practices 85.7% (highest BFSU). Rewrite because "atom" and "molecule" still don't appear.
BFSU K-2 lesson on kinetic and potential energy. Substance model deepened - energy "stored," "released," "flows like water out of a leaky bottle." Biology and technology framed via substance-flow chains. Foundation 0%, gap 100%, map error 57.9% (22 REI-substance). Same author thesis as C-1.
BFSU K-2 lesson distinguishing force from energy. Force content is descriptively correct (push/pull, gravity, spring scales, building design). Practices strong (78.6% green). The energy passages inherit substance framing from C-1/C-3 - force as "go-between" transferring stored energy. Foundation 0%, gap 100%, map error 17.9%.
BFSU K-2 lesson distinguishing matter from energy. Matter has three attributes (particulate, occupies space, has weight); energy "is what it is" - heat, light, electricity, motion. The author tells students to accept that energy has no deeper definition. Foundation 0%, gap 87.0%, map error 20.0% (3 AEC + 2 REI-substance).
BFSU K-2 lesson on inertia. Part 1 first-law content is descriptively solid (hands-on demos, careful pedagogy, distinguishing inertia from friction). Part 2 reconnects to BFSU substance-energy framework: "movement energy put into objects, removed by force." Foundation 0%, gap 84.6%, map error 17.1% (6 REI-substance).
BFSU K-2 lesson on friction. Friction-physics content is solid (surfaces, wheels, ball bearings, lubricants, streamlining). Part 3 installs substance framing: "energy inherent in motion that must come out as heat... energy defies being gathered up and recycled." Foundation 0%, gap 100%, map error 27.8% (10 REI-substance).
BFSU K-2 Newton's Third Law lesson. Door-push demo; "push pushes back with equal force." Applications: walking, balloons, jets, rockets, propellers, gun recoil. Practices 71.4% (green). Clean BFSU lesson - only 1 REI-substance phrase ("potential energy in fuel" in rocket synthesis). Foundation 0%, gap 100%, map 3.3%.
Mystery Science Grade 4 "Energizing Everything" defines energy as invisible "stuff" stored inside objects that travels and transfers - the substance misconception, asserted as fact - with no atomic grounding (100% gap, 12 reification errors). Foundation 0%: Shallow by design. Practices are scripted and low-agency (36%, amber); the physics is factually accurate.
Mystery Science Grade 1 "Lights & Sounds" avoids reification (no "sound/light is stuff") but uses "vibration" as a label-as-explanation (2 LAE errors), never naming what vibrates as sound travels. 100% gap, Foundation 0%. Shallow by default, not by design. Practices thin (29%, red). Factually accurate throughout.
Mystery Science Grade 2 "Material Properties" is sound observational materials science (classify properties, match to use) but the heat/insulation strand reifies heat as a substance that "travels through" materials (5 REI errors, by convention) with no particle grounding. Foundation 0%, Shallow by default. Practices 36% (amber). Factually accurate.
100% gap: four lessons on states of matter with zero mentions of atoms, molecules, or particles. Descriptions are clean (only 4.5% map error, 3 REI-agent) but students never learn what matter IS at the particle level. Clean-but-empty pattern. Practices 57.1% amber. Shallow by default.
Not Recommended (10 FSE flags: 1 confirmed, 9 review): oxygen defined as "a type of gas" rather than an element. 100% gap with 14 AEC errors: five lessons introduce a particle model but define particle as "a very tiny thing" with atoms and molecules never named. 10 total FSE flags (1 confirmed, 9 review) including water molecules called "droplets." Practices 42.9% (amber).
NGSS 1-PS4-aligned with explicit deferrals: light-as-energy → later elementary; speed of light → middle school; reflection's role in seeing → 4th grade. Most extreme practices/foundation split.
OpenSciEd Elem 2.2 (Grade 2 matter/engineering unit) - second OpenSciEd unit confirming pattern: 92.9% practices (high) + 0% Foundation (Not Recommended floor). Full engineering integration: students interview kindergartners, design toys, present to real audience.
OpenSciEd Elem 5.2 (Grade 5 matter properties) - The OpenSciEd Elementary unit that breaks the 0%-Foundation pattern. Foundation 82.4% RECOMMENDED. Practices 100% green - Particles introduced per NGSS 5-PS1-1; atomic-level mechanism still deferred.
OpenSciEd MS 6.1 (Grade 6 Light & Matter) - An OpenSciEd Middle School unit. Foundation 0% Not Recommended + 92.9% practices green. Wave/photon model explicitly deferred to Grade 8 - author voice calls this "a notable omission given the overarching Performance Expectation." K-Grade-6 Light thread reviewed; all three units at 0% Foundation.
OpenSciEd MS 6.2 (Grade 6 Thermal Energy) - Foundation 0% Not Recommended + 100% Practices green. NEW PATTERN: Particle-without-Atom. Unit has particle-based mechanism throughout but never specifies particles as atoms/molecules (except water in L4-6). 10 AEC errors flagged. Substance-model misconception surfaced as claim-to-test (excellent pedagogy).
OpenSciEd MS 6.6 (Grade 6 Cells & Systems / Healing) - An OpenSciEd biology unit. FIRST CONFIRMED FSE (Great Oxygenation Event misattributed to archaea instead of cyanobacteria). Foundation 0% Not Recommended + 92.9% Practices green. Cells-without-Molecules pattern (biology analog of 6.2 Particle-without-Atom).
OpenSciEd MS 7.1 (Grade 7 Bath Bombs) - Not Recommended (FSE policy). 2 confirmed FSEs in Lesson 14 Part 2b Assessment: (1) unbalanced Fe + H₂SO₄ equation with wrong products; (2) "Nitrous Oxide" labeled with NO₂ formula. Foundation 81% would otherwise be Conditional. Strong atoms-first pedagogy + 100% practices, but factual chemistry errors in summative assessment block recommendation.
OpenSciEd MS 7.2 (Grade 7 Homemade Heater) - HIGHEST FOUNDATION IN OPENSCIED CORPUS. Foundation 100% Recommended deep tier. Practices 100% green. Engineering design built on atomic chemistry from 7.1 + L2 atomic energy-transfer mechanism. Grade 7 chemistry (7.1 + 7.2) is OpenSciEd's atoms-first peak.
OpenSciEd MS 7.4 (Grade 7 Maple Syrup) - ✓ RECOMMENDED, Foundation 91.3%, deep tier. OpenSciEd biology unit that clears Recommended. Cellular respiration in mitochondria for both plants and animals. ⭐ Story of a Food Atom capstone (L14) traces ONE atom through producer/consumer/decomposer. Cellulose synthesis described as "reassemble the atoms." Practices 100% green. Zero FSEs after rigorous per-lesson assessment + answer key review.
OpenSciEd MS 8.1 (Grade 8, Broken Phone) - ✕ Not Recommended (Type 6 Clean-but-Empty). Foundation 0%, 100% gap, 0 map errors, 0 FSEs. Atoms/molecules/bonds never appear in 97-page Student Edition. ⭐ But practices 100% green - an engineering-rich unit (full design cycle, weighted Decision Matrix, interrater reliability, ½mv² systematic discovery). Not Recommended is gap-limited, not practices-limited.
OpenSciEd MS 8.2 (Grade 8, Sound Waves) - ✕ Not Recommended. Particle-without-Atom - a pronounced case. Student Edition contains 22 instances of "particle" and ZERO instances of "molecule" or "atom". High AEC rate (38.9%) in any OpenSciEd unit. Wave physics correct; entity unnamed. Practices 100% green. ⭐ One terminology pass would lift Foundation from 0% to ~100%.
OpenSciEd MS 8.3 (Grade 8, Magnets/Speaker) - ⟳ MINOR MODIFICATION, Foundation 66.2%, mid-deep tier. ⭐ ONLY OpenSciEd Grade 8 unit to engage atomic theory. "What is electric current?" reading explicitly names electrons and atoms; drift-speed discussion subtle and correct. Boundary-concept magnetism appropriately macroscopic. Practices 100% green. Three modest edits → Recommended.
RS4K Book 1 — Physics (Ch 10-13): K-2 force/work/energy chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 92.9%, no FSEs. Energy framed as a measurement of change, not a substance. Recommended Deep.
RS4K Book 2 — Chemistry (Ch 2-5): K-2 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 92.9%, no FSEs. Acids and bases differ at the atom-group level (OH for bases; H for acids). Acid-base reactions taught as atoms exchanging between molecules. Recommended Deep.
RS4K Book 2 — Physics (Ch 10-13): K-2 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 92.9%, no FSEs. Inertia grounded in mass, mass grounded in atoms, atoms made of protons/neutrons/electrons. Complete atoms-down derivation at K-2. Recommended Deep.
RS4K Book 2 — Geology (Ch 14-17): K-2 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 92.9%, no FSEs. Air named as N2/O2/CO2 molecules with atomic composition spelled out at K-2. Explicit nature-of-science framing. Recommended Deep.
RS4K Book 2 — Astronomy (Ch 18-21): K-2 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 92.9%, no FSEs. Telescopes, orbits, habitable zone, exoplanets all framed at appropriate scale. Greenhouse effect named as causal CO2 mechanism. Recommended Deep.
RS4K Book 3 — Biology (Ch 6-9): Grade 3 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 85.7%, no FSEs. Photosynthesis and respiration framed at atom-rearrangement level. Carbon cycle as atoms used over and over. Recommended Deep.
RS4K Book 3 — Physics (Ch 10-13): Grade 3 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 85.7%, no FSEs. Static electricity, conductivity, and ferromagnetism all grounded at electron level. Recommended Deep.
RS4K Book 3 — Geology (Ch 14-17): Grade 3 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 85.7%, no FSEs. Kinetic theory at K-3, water cycle as same molecules, magnetosphere correctly explained. Recommended Deep.
RS4K Book 5 — Chemistry (Ch 2–5): Grade 5 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 93%, no FSEs. Matter, periodic table, bonding, and reactions all built from atoms and electrons; conservation of matter as atom rearrangement. Recommended Deep.
RS4K Book 5 — Biology (Ch 6–9): Grade 5 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 100%, no FSEs. Cells, ATP, DNA, and metabolism anchored in atoms and molecules. Explicit correction that energy molecules do not contain energy. Three-week cell theory debate. Recommended Deep.
RS4K Book 5 — Physics (Ch 10–13): Grade 5 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 93%, no FSEs. Energy explicitly as measurement of change, not substance. Force as atomic contact. Friction as atomic handshakes. Full battery/flashlight atomic-level walkthrough. Recommended Deep.
RS4K Book 6 — Chemistry (Ch 2–5): Grade 6 atoms-first analytical chemistry. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 93%, zero FSEs. Acids/bases as ions, pH as hydrogen-ion concentration, moles, Avogadro’s number, nutritional biochemistry at bond level. Recommended Deep.
RS4K Book 6 — Biology (Ch 6–9): Grade 6 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 79%, no FSEs. Tool- and classification-focused (microscopy, protists, fungi). Where mechanism appears it is anchored: cells made of atoms, microbial feeding as molecular release and absorption. Recommended Deep.
RS4K Book 6 — Physics (Ch 10–13): Grade 6 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 86%, no FSEs. Newtonian mechanics and kinematics with heavy correct mathematics. Friction grounded in atoms rubbing. No reification of energy. Recommended Deep.
RS4K Book 6 — Astronomy (Ch 18–22): Grade 6 atoms-first chapters. Foundation 100%, Gap 0.0%, Map Error 0.0%, Practices 71%, no FSEs. Observational and tool-centered: telescopes, timekeeping, solar-system bodies, exoplanets. Where mechanism appears (stellar outbursts as charged particles) it is correct. Recommended Deep.
Grade 2–5 biology. 534 pages with zero instances of atom or molecule. DNA, cells, photosynthesis, respiration, and mutations all taught at the cellular/organ level with no atomic anchor. Confirmed factual error: plants make their own energy violates the first law of thermodynamics. Practices 92.9%.
Grade 2–5 chemistry. Atoms-first by design: Unit 2 builds protons, neutrons, electrons; Unit 3 builds the periodic table; later units build molecules, matter, and reactions from that foundation. 869 atom mentions across 433 pages. Foundation 100%, no map errors, no FSEs. Practices 92.9%.
Grade 3–6 physics. Atoms in Unit 1; electron-level mechanism dominates from Unit 6 onward (magnetism, electricity, quantum). Three Unit 5 passages frame potential energy as a substance stored in objects. Foundation 78.8%, 3 REI-substance errors, Practices 100%. Shallow by default.
100% gap, 74.3% map error: energy taught as transferable substance across 5 learning sets with zero atomic-molecular content. 26 errors in 35 student passages. Practices are 100% (3-5, Deep) but built entirely on the substance model. Shallow by design.
100% gap on 18 light and wave energy passages — light described without photon mechanism, wave energy framed as transferable substance. 1 confirmed FSE: water wave model used for light without distinguishing wave types. 22 clean observational passages on senses and eye anatomy. 100% practices.
78.6% gap with 9 AEC errors: 21 lessons on matter and chemical reactions build a particle model but define particle as “the smallest part of a material.” Carbon dioxide named in the plant growth context (4 TRUE passages), but atoms and molecules never anchor the particle concept. 100% practices.
Approved (boundary concept). Foundation: 100%. Practices: 78.6% (Deep). This K unit teaches pushes, pulls, and collisions accurately at the descriptive level. Zero map errors across 20 passages. No misconceptions introduced. Does not build atomic-molecular framework.
100% gap on 7 heat/temperature passages — the sun's warmth is never connected to photons or molecular motion. The 15 weather passages are clean and observational. 78.6% practices with genuine engineering design. The weather teaching is accurate; the heat teaching has no mechanism.
100% gap with zero map errors: 17 investigations build rigorous measurement of materials, weight, and volume without ever naming what materials are made of at the atomic level. Explicitly defers particle model to Grade 5. 85.7% practices with strong data collection and evidence-based claims.
100% gap with zero map errors: 16 investigations build rigorous measurement of density, weight conservation, and volume displacement in earth materials without connecting to atomic structure. “Heavy for size” replaces density but never explains WHY materials differ. Explicitly defers particle model. 92.9% practices.
100% gap with a complete particle model that never names the entity. 18 investigations build particles with weight, volume, and motion to explain dissolving, evaporation, condensation, and freezing — but “particle” is never defined as atom or molecule. Explicitly defers atomic terminology. 100% practices. One sentence from the fix.