{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.mass-density","code":"thing-q29539","url":"https://ver.cy/models/thing/q29539/","name":"mass density","alternateNames":["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"],"kind":"thing","status":"published","version":"0.2.0-wave.1","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.QLT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"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.","purpose":"Let an agent explain density by definition, measurement, typical values and applications such as buoyancy and materials selection.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Mass per volume","Depends on temperature and pressure","Determines buoyancy","Characteristic of materials"],"structure":{"bundles":[{"id":"concept","name":"Concept","description":"What it is.","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.","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.","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.","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"}]}]}]}]},"agentConduct":{"may":["Calculate and convert densities, stating units, temperature and pressure.","Explain relative density and how it relates to mass concentration."],"mustNot":["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."],"requiresHuman":["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."],"affectedParties":["Buyers and sellers","Engineers and operators"]},"owners":{"steward":"Nobody owns the quantity; metrology bodies maintain the units.","roles":[],"masterSystems":[]},"relations":[{"target":"Q107715","type":"parent","note":"registry parent class"},{"target":"Q137982797","type":"parent","note":"registry parent class"},{"target":"Q141187343","type":"parent","note":"registry parent class"},{"target":"Q141256417","type":"parent","note":"registry parent class"},{"target":"Q3387041","type":"parent","note":"registry parent class"},{"target":"Q41118","type":"parent","note":"registry parent class"},{"target":"physical quantity","type":"related","note":"category"},{"target":"kilogram per cubic metre","type":"related","note":"unit"},{"target":"buoyancy","type":"related","note":"effect"},{"target":"mass","type":"related","note":"quantity"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.mass-density","Wikidata: Q29539 (https://www.wikidata.org/wiki/Q29539)","SI unit: kg/m3 derived unit"]},"properties":{"applicability":"not-applicable","items":["density of water: about 1000 kg/m3 - near 4 degC"]},"recognition":{"applicability":"optional","items":["Units such as kg/m3 and g/cm3","Floating and sinking objects","Weight is a force, not density","Not visible; inferred from mass and volume or measured with hydrometers and densitometers."]},"capabilities":{"applicability":"required","items":["calculate density from mass and volume","look up density values with conditions","explain floating and sinking","convert between density units"]},"hazards":{"applicability":"required","items":["Ignoring temperature effects","Unit conversion errors"]},"interfaces":{"applicability":"required","items":["ISO and ASTM density test methods","OIML hydrometer recommendations"]},"context":{"applicability":"required","items":["Physics, engineering, chemistry and everyday estimation.","mass density","relative density and specific gravity","bulk and particle density","mass concentration in solutions","linear and area density"]}},"sources":[{"title":"Wikidata item Q29539: mass density","url":"https://www.wikidata.org/wiki/Q29539","note":"identity and sense of the item"},{"title":"Wikipedia: Density","url":"https://en.wikipedia.org/wiki/Density","note":"general description of the item"}],"openQuestions":["Should related densities be separate entries?","How should materials data be linked?","How should clinical concentrations be split off?"],"resources":{"spec":"/models/things/publications/thing-q29539/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q29539/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-11T12:34:42Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-06T19:51:58+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.properties":"Plane XCT: no invented physical properties."},"score":1.0}}