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PhysicalQuantity

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Physical quantities.

Entity["PhysicalQuantity",name] or

represents an entity of type "PhysicalQuantity".

[prop]

gives the value of a specified property.

[{propi,…}]

gives the value of a list of properties.

EntityClass["PhysicalQuantity",{propispeci,…}]

represents a class of entities with values of propi defined by speci.

Sample Entities

  • …

Sample Entity Classes

  • …

Properties

  • Abbreviationsabbreviations
    AlgebraicTypesalgebraic types
    AlternateNamesalternate names
    BasePhysicalQuantitybase physical quantity
    CanonicalUnitcanonical unit
    Classesclasses
    Dimensionsdimensions
    EntityClassesentity classes
    EntityTypeListentity type list
    Instancesinstances
    Namename
    NamedSIUnitnamed SI unit
    PhysicalPropertyTypephysical property type
    QuantityVariablequantity variable
    SIBaseUnitSI base unit
    SIUnitSI unit
    StandardIdentifiersstandard identifiers
    StandardSymbolsstandard symbols
    Symbolssymbols

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)Summary of the most common use cases

Use for entity discovery:

✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-mq38zi
Out[326]=326

Find a property value for an entity:

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-cxcz60
Out[1]=1

Retrieve a dataset of all available properties for an entity:

In[1]:=1
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https://wolfram.com/xid/0jvxspj4681an624x6cq-1o6cxi
Out[1]=1

Retrieve SI base physical quantities:

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-eer9vj
Out[1]=1

Return physical quantity entities that are instances of length:

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-slynn9
Out[1]=1

Scope  (1)Survey of the scope of standard use cases

Implicit Entity Classes  (1)

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

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-evj55j
Out[1]=1

Applications  (4)Sample problems that can be solved with this function

Physical quantity entities can be used with QuantityVariable:

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-kzbbuq
Out[1]=1

Physical quantity entities can be used with QuantityVariableCanonicalUnit:

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-nhp1lx
Out[1]=1

Compare with the corresponding physical quantity property:

In[2]:=2
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-4dxu0
Out[2]=2

Physical quantity entities can be used with QuantityVariableDimensions:

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-8999n2
Out[1]=1

Compare with the corresponding physical quantity property:

In[2]:=2
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-o2vj38
Out[2]=2

Physical quantity entities can be used with DimensionalCombinations:

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-w5bwae
Out[1]=1

Create a crosswalk to Wikidata identifiers:

In[2]:=2
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-jvnw6w
Out[2]=2

Relations to Other Entity Types  (2)

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

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-1dunxl
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-7nw1cl

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

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-rjoao6
Out[1]=1

Neat Examples  (2)Surprising or curious use cases

View the number of physical quantities by total absolute dimension:

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-binhje
In[2]:=2
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-hu7hj1
Out[2]=2

Plot the physical quantities with greatest absolute total dimensions:

In[3]:=3
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-4qr90l
In[4]:=4
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-253gdw
Out[4]=4

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

In[1]:=1
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-xz0j74

Collect all physical quantities containing only those dimensions:

In[2]:=2
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-8fsd4j

Convert dimension lists to vectors:

In[3]:=3
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-s5k5ye

Visualize as a feature space plot:

In[4]:=4
✖
https://wolfram.com/xid/0jvxspj4681an624x6cq-f1p5ry
Out[4]=4