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%.
| Program | OpenSciEd Middle School |
| Unit | Grade 8, Unit 8.2: Sound Waves (Truck Speaker → Window) |
| Publisher | OpenSciEd |
| Author | OpenSciEd Curriculum Development Team |
| Grade Band | Grade 8 (6-8 calibration applied) |
| NGSS Alignment | MS-PS4-1, MS-PS4-2, MS-LS1-8 |
Verdict: ✕ Not Recommended. Foundation_calc 0.0%, shallow tier. Practices 100% green. Pattern: Particle-without-Atom - a pronounced case.
The Student Edition contains 22 instances of the word "particle" and zero instances of "molecule" or "atom". The unit's central modeling entity - the thing that transmits compression waves through solid, liquid, and gas media - is named "particles" throughout, but never identified as molecules of air, water molecules, or atoms in solids. The "particles" are generic - the textbook vague-entity construction (AEC) the WWG framework was built to flag.
Map error rate: 38.9% AEC - the highest. Seven of 18 mechanism passages tag AEC, clustered in L9 body-simulation (×3), L10 computer simulation + home learning (×3), and L12 ears (×1).
5.2 introduced particles atomically; 6.2 retreated to generic particles (Particle-without-Atom); 7.1 introduced Dalton's atoms but Not Recommended (FSE) for FSEs; 7.4 atom-tracked biology cleanly (Recommended 91.3%); 8.1 returned to macroscopic-only (Type 6); 8.2 retains 6.2's generic-particle framework at higher density. The atomic-grounding work done in 5.2 and 7.4 is not carried forward.
Anchored on a striking phenomenon: music from a truck speaker makes a window across a parking lot vibrate.
L1-6 (Sound production): Vibration → sound. L4 motion-detector amplitude (louder = greater amplitude). L5 frequency/pitch.
L7-8 (What's moving?): L7 air doesn't move all the way. L8 bell-jar vacuum: air (or some medium) is required.
⭐ L9 (Particle body-simulation): Volunteers line up to represent "particles." Sound source pushes first particle; particle hits next; wave propagates. Word "particle" never anchored.
⭐ L10 (Computer simulation + home learning): "Scientists often build computer simulations to help investigate and visualize outcomes in systems that have parts (or particles) in them that are too small to see." Home-learning directive: "include in your model: vibrations of the sound source; collisions between particles; energy transfer; changes that happen in the particle density across the medium." The unit's articulated framework.
L11 (Bouncing salt): Drum strike → salt bounces. Gallery walk with structured sticky-note critique - strongest peer-feedback structure.
L12 (Ears): "What do you think happens when these kinds of particle compression waves hit human ears?" AEC carried into ear anatomy.
L13 (Energy): Ruler-and-marble investigation with class data + explicit outlier-handling. Energy depends on both amplitude and frequency. Quantitatively rigorous, atomically silent.
L14: Apply model to truck-speaker-window anchor.
⭐ "Make a sketch of what is happening and be sure to include the following in your model: vibrations of the sound source; collisions between particles; energy transfer; changes that happen in the particle density across the medium." (L10 home learning) - The unit's articulated framework. Mechanism correct; entity unnamed.
⭐ "Volunteers line up... to represent particles. The new particle that is hit starts moving toward the next particle. This process repeats every time a particle hits another particle." (L9 body-simulation) - Kinesthetic experience anchors "particles" in students' bodies. None identified.
"Scientists often build computer simulations to help investigate and visualize outcomes in systems that have parts (or particles) in them that are too small to see." (L10) - Student-facing acknowledgment that particles are sub-visible - but never that they have names, formulas, masses, or chemistry.
"What do you think happens when these kinds of particle compression waves hit human ears?" (L12) - AEC carried into ear anatomy.
FSE_CONFIRMED: 0. Wave mechanism is physically correct: compression waves, particle density changes, energy transfer via collisions are accurate. Amplitude-loudness and frequency-pitch relationships correct. L13 energy conclusion correct. L8 vacuum result correctly attributed. The unit's failure mode is AEC, not FSE.
Practices: 100% green - high. All seven applicable practices INTENTIONALLY_DEVELOPED. Strongest peer-feedback structure - L11 sticky-note critique formats. Three model types (diagrammatic + body-sim + computer-sim). L13 outlier-handling is unique to 8.2.
One terminology pass replacing "particles" with the molecular entity in each medium:
After these edits: AEC count 7 → 0; adjusted gap 100% → ~0%; Foundation_calc 0% → ~100% (Recommended, deep tier). The physics, investigations, and practices work all remain unchanged. This is the the most direct improvement path for this unit - one terminology pass.
Particle-without-Atom - pronounced. Where 8.1 makes no contact with sub-visible scale at all (Type 6 Clean-but-Empty), 8.2 commits to a sub-visible model but stops short of identifying what the modeled entities are.
| Total Passages Scored | 30 |
| Raw Gap Error | 100.0% (18/18 mechanism passages - no atoms/molecules named anywhere in unit) FALSE = atoms/molecules not present before students are asked to explain. The student is navigating without a starting point. |
| Adjusted Gap Error | 100.0% (18/18 UNSCAFFOLDED - atoms never introduced in unit) UNSCAFFOLDED = no atomic grounding at all. LESSON_ATOMS = atoms mentioned elsewhere in lesson but not connected to this concept. |
| Substance-Model Errors (REI) | 0 Curriculum treats a process or outcome as a substance - "heat flows," "energy is stored," "electricity flows like water." Student builds a substance ontology. |
| Label-as-Explanation (LAE) | 0 Curriculum provides a name and treats it as an explanation - "this happens because of gravity." Student believes knowing the name IS understanding the concept. |
| Vague-Entity Errors (AEC) | 7 Curriculum uses vague entities ("tiny particles," "building blocks") without specifying atoms or molecules. Student invents their own model with macroscopic properties. |
| Factual Science Errors (FSE) | 0 Statements that are scientifically incorrect - not imprecise framing, but wrong. Any confirmed FSE = Not Recommended. |
| Practices | 100% - Deep Seven practices scored PRESENT, PARTIAL, or ABSENT and averaged: asking questions, developing and using models, planning and carrying out investigations, analyzing and interpreting data, using mathematics, constructing explanations and designing solutions, and argument from evidence. Higher is better, the opposite direction from gap and map errors. Reported but not part of the Foundation Score or the verdict. |
Particle-without-Atom - pronounced. 22 occurrences of "particle"; 0 of "molecule" or "atom" in Student Edition (confirmed by direct text search). High AEC rate (38.9%). Wave physics correct; entity unnamed. One terminology pass would lift Foundation from 0% to ~100% - the most direct improvement path for this unit.
Strongest peer-feedback structure (L11 sticky-note critique formats: "Your model said X. I disagree because Y. I think you should change Z."). Three model types: diagrammatic + body-simulation + computer-simulation. L13 explicit outlier-handling methodology is unique to 8.2. 100% practices.
shallow by default (Particle-without-Atom) - Student Edition direct text search: 22 "particle" / 0 "molecule" / 0 "atom". L9 body-simulation, L10 computer simulation + home learning, L12 ears - all built on generic "particles." Wave mechanism (compression waves, particle density changes, energy transfer via collisions) is physically correct but the modeling entity is never identified. Air molecules, water molecules, atoms in solids - the actual entities - never named.
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