PhysicalQuantity

Physical quantities.

Entity["PhysicalQuantity",name] or

represents an entity of type "PhysicalQuantity".

[prop]

gives the value of a specified property.

[{prop_i,…}]

gives the value of a list of properties.

EntityClass["PhysicalQuantity",{prop_ispec_i,…}]

represents a class of entities with values of prop_i defined by spec_i.

Sample Entities

Sample Entity Classes

Properties

	Abbreviations	abbreviations
	AlgebraicTypes	algebraic types
	AlternateNames	alternate names
	BasePhysicalQuantity	base physical quantity
	CanonicalUnit	canonical unit
	Classes	classes
	Dimensions	dimensions
	EntityClasses	entity classes
	EntityTypeList	entity type list
	Instances	instances
	Name	name
	NamedSIUnit	named SI unit
	PhysicalPropertyType	physical property type
	QuantityVariable	quantity variable
	SIBaseUnit	SI base unit
	SIUnit	SI unit
	StandardIdentifiers	standard identifiers
	StandardSymbols	standard symbols
	Symbols	symbols

Details

"PhysicalQuantity" entities include named physical properties that can be quantified by measurement, including length, mass, time, speed, force, etc.
"PhysicalQuantity" entity classes include groups of physical quantities that count entities, are instances of a more general quantity, are base quantities in the SI system of units, etc.
Some properties are available for the "PhysicalQuantity" entity type as a whole and can be given using the form EntityValue["PhysicalQuantity",property ]. Such properties include:

	"Properties"	the list of available properties
	"PropertyCanonicalNames"	the standard names of available properties
	"SampleEntities"	a sample list of available entities (typically of length 10)
	"SampleEntityClasses"	a sample list of available entity classes (typically of length 10)
	"EntityCount"	number of entities available
	"Entities"	the list of available entities
	"EntityCanonicalNames"	the standard names of available entities
	"EntityClasses"	the list of available entity classes
	"EntityClassCanonicalNames"	the standard names of available entity classes
	"PropertyClasses"	the list of available property classes
	"PropertyClassCanonicalNames"	the standard names of available property classes
	"PropertyCount"	number of properties available

The following annotations can be used in the third argument of EntityValue["PhysicalQuantity",property,annotation]:

	"Source"	source information for the property
	"Date"	the date associated with the entity-property value (if any)
	"EntityAssociation"	an association of entities and entity-property values
	"PropertyAssociation"	an association of properties and entity-property values
	"EntityPropertyAssociation"	an association in which the specified entities are keys, and values are a nested association of properties and entity-property values
	"PropertyEntityAssociation"	an association in which the specified properties are keys, and values are a nested association of entities and entity-property values
	"Dataset"	a dataset in which the specified entities are keys, and values are an association of property names and entity-property values

The following annotations can be used in the second argument of EntityValue[property,annotation]:

	"Qualifiers"	the list of possible qualifiers for the property
	"QualifierValues"	the list of possible values that can be given to each qualifier
	"DefaultQualifierValues"	the list of default values for the property's qualifiers
	"Description"	a brief textual description of the property
	"Definition"	a detailed textual definition of the property
	"PhysicalQuantity"	the physical quantity associated with the entity-property value
	"Unit"	the unit associated with the entity-property value

A qualifier value of Automatic indicates that an applicable format of values can be used; e.g. for the "Date" qualifier, this includes a proper date or date span.

Examples

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Basic Examples (5)

Use for entity discovery:

Find a property value for an entity:

Retrieve a dataset of all available properties for an entity:

Retrieve SI base physical quantities:

Return physical quantity entities that are instances of length:

Scope (1)

Implicit Entity Classes (1)

Retrieve physical quantities with dimensions of [mass]/[time]:

Applications (4)

Physical quantity entities can be used with QuantityVariable:

Physical quantity entities can be used with QuantityVariableCanonicalUnit:

Compare with the corresponding physical quantity property:

Physical quantity entities can be used with QuantityVariableDimensions:

Compare with the corresponding physical quantity property:

Physical quantity entities can be used with DimensionalCombinations:

Create a crosswalk to Wikidata identifiers:

Relations to Other Entity Types (2)

Use FromEntity to convert from a physical quantity entity to a quantity variable:

Use ToEntity to convert a quantity variable to a physical quantity entity:

Neat Examples (2)

View the number of physical quantities by total absolute dimension:

Plot the physical quantities with greatest absolute total dimensions:

Visualize the dimensionality of physical quantities based on the standard dimensions:

Collect all physical quantities containing only those dimensions:

Convert dimension lists to vectors:

Visualize as a feature space plot:

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