{ "model": { "rank": 1837, "code": "thing-q29539", "model_id": "vr.tr.mass-density", "name": "mass density", "purpose": "Let an agent explain density by definition, measurement, typical values and applications such as buoyancy and materials selection.", "family": "Thing Registry", "category": "Cross-cutting context", "status": "research-draft", "kind": "thing", "plane": "XCT", "domain": "XCT.QLT", "industry": "", "version": "", "url": "/models/thing/q29539/", "tier": 2, "score": 125, "payload": { "layer": "wikidata", "aliases": [ "serum sodium level", "mean corpuscular hemoglobin concentration", "relative density", "particle density", "mass concentration", "mass concentration of water", "mass concentration of water vapour", "mass concentration of water vapour at saturation", "baricity", "mass density of solid particles", "fluid mass density", "density of heavier fluid", "density of lighter fluid", "mass density of bubble or drop", "mass density of body", "mass density of bubbles", "liquid density", "reference density", "tree density", "gas density", "cosmic density", "density of air", "stowage factor", "critical density", "oil density", "basic density", "green density", "air-dried density", "lighter-than-air", "bulk density", "mean mass density", "hemoglobinometry", "serum C reactive protein level", "serum ferritin", "serum total protein", "serum calcium", "phosphatemia", "serum iron", "serum total cholesterol level", "blood lithium level" ], "aliasCount": 64, "merged": 65, "knownIn": 125, "facets": null, "markers": [], "lexicalClass": "", "senseRank": null, "alsoRegisteredAs": null, "source": { "dataset": "wikidata", "item": "Q29539", "url": "https://www.wikidata.org/wiki/Q29539", "license": "CC0 1.0" } }, "research": { "vercy": "1.0-draft", "publication": { "status": "research-draft", "adjudicationStatus": "unreviewed", "publishableCanonical": false, "generatedAt": "2026-09-11T12:34:42Z", "providers": [ "Claude" ], "breadth": "written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify", "pass": 2, "wave": 1, "engine": "claude" }, "metaModel": { "id": "THING-Q29539", "registryId": "vr.tr.mass-density", "name": "mass density", "version": "0.2.0-wave.1", "entryKind": "thing", "family": "Thing Registry", "domain": [ "XCT.QLT" ], "status": "research-draft" }, "canonicalUrl": "https://ver.cy/models/thing/q29539/", "model": { "registry_id": "vr.tr.mass-density", "name": "mass density", "purpose": "Let an agent explain density by definition, measurement, typical values and applications such as buoyancy and materials selection.", "definition": "The mass of a substance per unit volume, symbol rho, measured in kilograms per cubic metre (kg/m3); water has a density of about 1000 kg/m3 near 4 degC, and related quantities include relative density (specific gravity) and mass concentration.", "what_it_is_for": "Physics, engineering, chemistry and everyday estimation.", "affordances": [ "calculate density from mass and volume", "look up density values with conditions", "explain floating and sinking", "convert between density units" ], "distinguishing_features": [ "Mass per volume", "Depends on temperature and pressure", "Determines buoyancy", "Characteristic of materials" ], "appearance": "Not visible; inferred from mass and volume or measured with hydrometers and densitometers.", "visual_identification": [ "Units such as kg/m3 and g/cm3", "Floating and sinking objects", "Weight is a force, not density" ], "physical_properties": [ { "quantity": "density of water", "typical_range": "about 1000", "unit": "kg/m3", "note": "near 4 degC" } ], "families_and_kinds": [ "mass density", "relative density and specific gravity", "bulk and particle density", "mass concentration in solutions", "linear and area density" ], "related_models": [ { "relation": "is a kind of", "target": "physical quantity", "why": "category" }, { "relation": "is measured in", "target": "kilogram per cubic metre", "why": "unit" }, { "relation": "determines", "target": "buoyancy", "why": "effect" }, { "relation": "is related to", "target": "mass", "why": "quantity" } ], "identifiers": [ { "scheme": "SI unit", "value_or_pattern": "kg/m3", "note": "derived unit" } ], "standards_and_regulation": [ "ISO and ASTM density test methods", "OIML hydrometer recommendations" ], "failure_modes_and_hazards": [ "Ignoring temperature effects", "Unit conversion errors" ], "in_scope": [], "out_of_scope": [], "characteristics": [] }, "sources": [], "structure": { "bundles": [ { "id": "concept", "name": "Concept", "description": "What it is.", "rationale": "Mass per volume.", "layers": [ { "id": "calculate", "name": "Calculate", "description": "Formula.", "findings": [ { "id": "calculate-finding", "name": "Calculate", "description": "Calculation.", "questions": [ { "text": "What is the density given this mass and volume?", "kind": "measurement" }, { "text": "Are the units consistent?", "kind": "boundary" } ] } ] }, { "id": "relative", "name": "Relative", "description": "Specific gravity.", "findings": [ { "id": "relative-finding", "name": "Relative", "description": "Relative density.", "questions": [ { "text": "What is the relative density compared with water?", "kind": "measurement" }, { "text": "At which reference temperature?", "kind": "definition" } ] } ] } ] }, { "id": "values", "name": "Values", "description": "Data.", "rationale": "Values depend on conditions.", "layers": [ { "id": "lookup", "name": "Lookup", "description": "Tables.", "findings": [ { "id": "lookup-finding", "name": "Lookup", "description": "Reference values.", "questions": [ { "text": "What is the density of this material, according to reference data?", "kind": "provenance" }, { "text": "At what temperature and pressure?", "kind": "measurement" } ] } ] }, { "id": "conditions", "name": "Conditions", "description": "Temperature effects.", "findings": [ { "id": "conditions-finding", "name": "Conditions", "description": "Temperature effects.", "questions": [ { "text": "How does density change with temperature for this substance?", "kind": "measurement" }, { "text": "Why is water densest near 4 degC?", "kind": "definition" } ] } ] } ] }, { "id": "measurement", "name": "Measurement", "description": "Methods.", "rationale": "Methods vary.", "layers": [ { "id": "methods", "name": "Methods", "description": "Instruments.", "findings": [ { "id": "methods-finding", "name": "Methods", "description": "Measurement methods.", "questions": [ { "text": "Which method suits this sample, such as a hydrometer or pycnometer?", "kind": "definition" }, { "text": "Which standard applies?", "kind": "provenance" } ] } ] }, { "id": "displacement", "name": "Displacement", "description": "Archimedes.", "findings": [ { "id": "displacement-finding", "name": "Displacement", "description": "Displacement method.", "questions": [ { "text": "How can volume be found by water displacement?", "kind": "action" }, { "text": "What errors arise?", "kind": "boundary" } ] } ] } ] }, { "id": "applications", "name": "Applications", "description": "Uses.", "rationale": "Density matters in practice.", "layers": [ { "id": "buoyancy", "name": "Buoyancy", "description": "Floating.", "findings": [ { "id": "buoyancy-finding", "name": "Buoyancy", "description": "Buoyancy.", "questions": [ { "text": "Will this object float in this liquid?", "kind": "boundary" }, { "text": "How does Archimedes principle explain it?", "kind": "definition" } ] } ] }, { "id": "materials", "name": "Materials", "description": "Selection.", "findings": [ { "id": "materials-finding", "name": "Materials", "description": "Materials selection.", "questions": [ { "text": "Which material gives the needed strength for the lowest density?", "kind": "measurement" }, { "text": "Which database lists properties?", "kind": "provenance" } ] } ] } ] } ] }, "openQuestions": [ "Should related densities be separate entries?", "How should materials data be linked?", "How should clinical concentrations be split off?" ], "statistics": { "bundles": 4, "layers": 8, "findings": 8, "questions": 16 } }, "draft": { "generator": "vr.draft.v3", "status": "draft-generated", "researched": false, "archetype": "abstract concept", "method": "Written from the archetype playbook - what this kind of thing needs beyond identity and provenance - and from the structure that recurred across 6,333 models already researched by two engines. Applied to this entry by rule. No source was read for this thing and no claim here is researched. This entry carries no facets of its own, so they were inferred from its domain - a guess about a whole domain applied to one thing.", "facetsInferred": true, "nextPass": "A researcher replaces this draft with a sourced specification. Treat every sentence below as a proposal to argue with.", "purpose": "Give an agent a durable, checkable way to recognise a mass density, record what state it is in, and decide what may be done with it.", "whatItIs": "Let an agent explain density by definition, measurement, typical values and applications such as buoyancy and materials selection.", "characteristics": { "substance": "abstract", "origin": "conceptual", "agency": "inert" }, "whatYouCanDoWithIt": [ "observed and measured" ], "distinguishingFeatures": [ "Names folded into this entry, which a task may need to split apart again: serum sodium level, mean corpuscular hemoglobin concentration, relative density, particle density, mass concentration, mass concentration of water, mass concentration of water vapour, mass concentration of water vapour at saturation, baricity, mass density of solid particles, fluid mass density, density of heavier fluid.", "65 finer distinctions are held as aliases rather than separate entries, because telling them apart needs a task that asks for it.", "Described in 125 Wikipedia languages, which is a measure of how widely the thing is known, not of how important it is." ], "openQuestionsForResearch": [ "Which of the bundles below does a real task actually need, and which are ceremony?", "What does this thing have that the facets do not capture at all?", "Which neighbouring kind is most often confused with a mass density, and on what evidence are they told apart?" ], "whatItIsMadeOf": "an abstraction with no physical instance", "physicalCharacter": [ "Does nothing on its own; everything it does, something else did to it.", "These come from the domain this entry sits in rather than from the entry itself, so treat them as a first guess about the whole domain applied to one thing." ], "whatCanBeDoneWithIt": [ "observe it, measure it, record its state" ], "howItIsRecognised": [ "Nothing to see. What is recognised is an instance of it, and which instances count is exactly what is argued about." ], "relatedModels": [ { "relation": "covers", "note": "Finer kinds folded into this entry because telling them apart needs a task that asks for it. Each is a model waiting to be split out when one does.", "targets": [ "serum sodium level", "mean corpuscular hemoglobin concentration", "relative density", "particle density", "mass concentration", "mass concentration of water", "mass concentration of water vapour", "mass concentration of water vapour at saturation", "baricity", "mass density of solid particles", "fluid mass density", "density of heavier fluid" ] } ], "standing": "Described in 125 Wikipedia languages, which measures how widely it is written about rather than how important or how common it is. 65 finer distinctions are held inside this entry as names rather than as separate models.", "structure": { "bundles": [ { "id": "identity-and-classification", "name": "Identity, naming and classification", "description": "How an agent tells one mass density from another, and a mass density from things that resemble it.", "rationale": "Recognition comes before every other claim. Without stable identity nothing else in the model can be trusted to be about the same thing twice.", "layers": [ { "id": "naming-and-identifiers", "name": "Names and identifiers", "description": "The names this thing goes by and the identifiers that survive translation and time.", "findings": [ { "id": "preferred-name-and-aliases", "name": "Preferred name, aliases and local names", "description": "Which name to use, which names mean the same thing, and which merely sound similar.", "questions": [ { "id": "preferred-name-and-aliases-q01", "text": "What identifies and describes the name of a mass density, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "preferred-name-and-aliases-q02", "text": "Who or what asserted this about the name of a mass density, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "preferred-name-and-aliases-q03", "text": "What may an agent decide or do once the name of a mass density is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "stable-identifiers", "name": "Stable identifiers and external keys", "description": "Identifiers that keep pointing at this kind of thing across systems and languages.", "questions": [ { "id": "stable-identifiers-q01", "text": "What identifies and describes an identifier for a mass density, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stable-identifiers-q02", "text": "Who or what asserted this about an identifier for a mass density, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stable-identifiers-q03", "text": "What may an agent decide or do once an identifier for a mass density is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "classification-and-granularity", "name": "Classification and granularity", "description": "Where a mass density sits among kinds, and how finely a task needs to cut it.", "findings": [ { "id": "kind-and-parents", "name": "Kind, parents and neighbouring kinds", "description": "The classes this thing belongs to and the ones it is next to.", "questions": [ { "id": "kind-and-parents-q01", "text": "What identifies and describes the kind of a mass density, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "kind-and-parents-q02", "text": "Who or what asserted this about the kind of a mass density, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "kind-and-parents-q03", "text": "What may an agent decide or do once the kind of a mass density is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "distinguishing-features", "name": "Distinguishing features", "description": "What separates a mass density from the things most often confused with it.", "questions": [ { "id": "distinguishing-features-q01", "text": "What identifies and describes what distinguishes a mass density, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "distinguishing-features-q02", "text": "Who or what asserted this about what distinguishes a mass density, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "distinguishing-features-q03", "text": "What may an agent decide or do once what distinguishes a mass density is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "state-and-lifecycle", "name": "State and lifecycle", "description": "The states a mass density passes through and the events that move it between them.", "rationale": "Most decisions about a thing depend on what state it is in now, which is a claim with a time on it, not a property.", "layers": [ { "id": "lifecycle-stages", "name": "Lifecycle stages", "description": "From coming into existence to ceasing to be one of these.", "findings": [ { "id": "stages-and-transitions", "name": "Stages and transitions", "description": "The stages worth naming and what moves a mass density between them.", "questions": [ { "id": "stages-and-transitions-q01", "text": "What identifies and describes the lifecycle of a mass density, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stages-and-transitions-q02", "text": "Who or what asserted this about the lifecycle of a mass density, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stages-and-transitions-q03", "text": "What may an agent decide or do once the lifecycle of a mass density is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "observations-and-status", "name": "Observations and current status", "description": "What is observed about a mass density, how often and by whom.", "findings": [ { "id": "observation-record", "name": "Observation record", "description": "How an observation of a mass density is recorded so that it can be superseded rather than overwritten.", "questions": [ { "id": "observation-record-q01", "text": "What identifies and describes an observation of a mass density, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "observation-record-q02", "text": "Who or what asserted this about an observation of a mass density, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "observation-record-q03", "text": "What may an agent decide or do once an observation of a mass density is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "definitions-in-contest", "name": "Definitions and who holds them", "description": "What mass density is taken to mean, and by whom.", "rationale": "When a field disagrees about a concept, the disagreement is the content. A model that picks one definition silently destroys the information.", "layers": [ { "id": "competing-definitions", "name": "Competing definitions", "description": "The main readings and the traditions behind them.", "findings": [ { "id": "definition-map", "name": "Definitions and their holders", "description": "Each definition with the school or body that holds it.", "questions": [ { "id": "definition-map-q01", "text": "Which definitions of mass density are in use, and which tradition or body holds each?", "kind": "definition" }, { "id": "definition-map-q02", "text": "What turns on the difference between them in practice?", "kind": "boundary" } ] } ] }, { "id": "operationalisation", "name": "Operationalisation", "description": "How it is measured or applied when it has to be.", "findings": [ { "id": "operational-record", "name": "Measures and proxies", "description": "Instruments and indicators used to stand in for it.", "questions": [ { "id": "operational-record-q01", "text": "How is mass density operationalised or measured in practice, and by what instrument?", "kind": "measurement" }, { "id": "operational-record-q02", "text": "What does that operationalisation leave out, and when does that matter?", "kind": "boundary" } ] } ] } ] }, { "id": "instances-and-use", "name": "Instances, use and consequence", "description": "What counts as an instance of mass density and what follows from calling something that.", "rationale": "Applying a concept is an act with consequences, so a model must say what the label licenses and what it does not.", "layers": [ { "id": "instances", "name": "What counts as an instance", "description": "Clear cases, borderline cases and non-cases.", "findings": [ { "id": "instance-tests", "name": "Tests for an instance", "description": "What would settle whether something falls under it.", "questions": [ { "id": "instance-tests-q01", "text": "What would settle whether something is an instance of mass density?", "kind": "boundary" }, { "id": "instance-tests-q02", "text": "Which borderline cases are argued about, and on what grounds?", "kind": "definition" } ] } ] }, { "id": "consequence", "name": "Consequence of application", "description": "Rights, duties or decisions that follow from the label.", "findings": [ { "id": "consequence-record", "name": "What the label licenses", "description": "What an agent may do once something is classified this way.", "questions": [ { "id": "consequence-record-q01", "text": "What follows practically once something is treated as mass density?", "kind": "action" }, { "id": "consequence-record-q02", "text": "What must an agent not infer from the label alone?", "kind": "action" } ] } ] } ] }, { "id": "provenance-and-evidence", "name": "Provenance, evidence and time", "description": "Where every claim about a mass density came from and when it held.", "rationale": "A claim without a source and a time cannot be superseded, only overwritten, and an agent that overwrites loses the ability to explain itself.", "layers": [ { "id": "source-and-authority", "name": "Source and authority", "description": "Who said it, on what evidence, and how strongly.", "findings": [ { "id": "claim-provenance", "name": "Claim provenance and confidence", "description": "The authority behind each claim about a mass density and how confident it is.", "questions": [ { "id": "claim-provenance-q01", "text": "What identifies and describes a claim about a mass density, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "claim-provenance-q02", "text": "Who or what asserted this about a claim about a mass density, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "claim-provenance-q03", "text": "What may an agent decide or do once a claim about a mass density is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "time-and-versions", "name": "Time, versions and supersession", "description": "When a claim was true, when it was learnt, and what replaced it.", "findings": [ { "id": "validity-and-supersession", "name": "Validity period and supersession", "description": "How an old claim about a mass density is retired without being erased.", "questions": [ { "id": "validity-and-supersession-q01", "text": "What identifies and describes the validity of a claim about a mass density, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "validity-and-supersession-q02", "text": "Who or what asserted this about the validity of a claim about a mass density, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "validity-and-supersession-q03", "text": "What may an agent decide or do once the validity of a claim about a mass density is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] } ] }, "statistics": { "bundles": 5, "layers": 10, "findings": 12, "questions": 32 } } } }