{
  "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",
    "enrichment": {
      "pass": 3,
      "engine": "claude",
      "producedAt": "2026-10-05T17:00:00Z",
      "ingestedAt": "2026-10-05T13:29:21+00:00",
      "fields": [
        "agent_conduct",
        "ethics",
        "owners"
      ]
    },
    "gate": {
      "passed": true,
      "version": "1.0",
      "at": "2026-10-06T19:51:58+00:00",
      "evidence": [
        "completeness 1.00",
        "sense: Wikidata description",
        "2 live sources",
        "review by codex: pass"
      ]
    }
  },
  "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": [],
    "agent_conduct": {
      "may": [
        "Calculate and convert densities, stating units, temperature and pressure.",
        "Explain relative density and how it relates to mass concentration."
      ],
      "must_not": [
        "Ignore temperature effects when using density for quantity or safety calculations.",
        "Mix units without stating them.",
        "Present density as proof of authenticity or purity of a material without other tests."
      ],
      "requires_human": [
        "Using a density figure to set a load, a dose or a trade valuation."
      ]
    },
    "ethics": {
      "considerations": [
        "Wrong density figures can cause overloaded vessels and short-measured goods."
      ],
      "affected_parties": [
        "Buyers and sellers",
        "Engineers and operators"
      ]
    },
    "owners": {
      "steward": "Nobody owns the quantity; metrology bodies maintain the units.",
      "master_systems": []
    }
  },
  "sources": [
    {
      "id": "wikidata",
      "title": "Wikidata item Q29539: mass density",
      "url": "https://www.wikidata.org/wiki/Q29539",
      "url_status": "live",
      "what_it_supports": "identity and sense of the item",
      "checked_by": "wikidata-api"
    },
    {
      "id": "wikipedia-en",
      "title": "Wikipedia: Density",
      "url": "https://en.wikipedia.org/wiki/Density",
      "url_status": "live",
      "what_it_supports": "general description of the item",
      "checked_by": "wikidata-api sitelink"
    }
  ],
  "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
  }
}