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Research draft

quantity

vr.tr.quantity · XCT.QLT

Let an agent identify and handle quantities correctly, explain quantity types and units, and support measurement, calculation and comparison.

Thing Registry Cross-cutting context

Research draft, second pass

A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.

written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify

Researched by: Claude

Purpose and description

Let an agent identify and handle quantities correctly, explain quantity types and units, and support measurement, calculation and comparison.

A property of a thing that can be measured, counted or compared, expressed as a number with or without a unit, such as length, mass, temperature, count or amount of money; quantities are the subject of measurement science, distinguished as base or derived, scalar or vector, and extensive or intensive.

What it is for: Measurement and quantitative reasoning.

It can be identify a quantity and its unit; classify quantities; convert and compare quantities; explain measurement concepts.

Distinguishing features

Measurable

Number and unit

Typed by nature

Foundation of science

What it looks like

Not physical; numbers with units.

How it is recognised

Measurable property

Number and unit

A quality is not measurable on a numeric scale

Related models

is a kind of - category

property

is a kind of - category

value

includes - kind

vector quantity

is related to - specific amounts

definite-quantity

In practice

Families and kinds

base and derived quantities

scalar and vector quantities

extensive and intensive quantities

counts and dimensionless quantities

monetary quantities

Standards and regulation

International System of Quantities and ISO 80000

SI units

Metrology vocabulary (VIM)

Failure modes and hazards

Unit errors

Confusing quantity with unit

Adding incompatible quantities

Where this came from

wikidata · CC0 1.0

Also registered as vr.tr.quantity

Drafted structure

Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.

Identify What quantity.

Quantity and unit.

Which

Identifying the quantity.

Which

Identification.

  1. Which quantity is being measured or discussed, and what is its unit and dimension? definition
  2. Is it a base or derived quantity? definition

Type

Classification.

Type

Classification.

  1. Is the quantity scalar or vector, extensive or intensive? definition
  2. Why does the distinction matter here? definition
Measure Measurement.

Uncertainty.

Method

How measured.

Method

Method.

  1. How is this quantity measured, and with what instruments? provenance
  2. What is the measurement uncertainty? measurement

Standards

Quantity standards.

Standards

Standards.

  1. How do ISO 80000 and the SI define this quantity and its unit? provenance
  2. Which symbol should be used? provenance
Compute Working with quantities.

Dimensional consistency.

Operations

Combining quantities.

Operations

Operations.

  1. Can these quantities be added or compared, and are the units compatible? boundary
  2. What is the result with correct units? measurement

Convert

Conversion.

Convert

Conversion.

  1. How does this quantity convert between unit systems? measurement
  2. Is the conversion exact? boundary
Teach Concepts.

Quantity versus number.

Concepts

Quantity concepts.

Concepts

Concepts.

  1. How do quantity, value, number and unit relate? definition
  2. Which misconceptions arise? provenance

Senses

Other senses.

Senses

Other senses.

  1. Is quantity meant as an amount of goods, a logical quantifier or a mathematical concept? boundary
  2. Which entry fits? action

What the second pass must settle

  • Should each quantity type be a separate entry?
  • How should ISO 80000 be linked?
  • How should measurement uncertainty be recorded?