Physics Ontology

One map of physics, three ways in. Drill down on any quantity to see its units, the equations it lives in, and how its values span the universe.

QuantitiesAreas & EquationsTimeline
← Back to all quantities
QQ
Thermodynamics

Heat

Energy transferred due to a temperature difference.

SI unit

joule (J)

Dimension: [ ML2T−2 ][\,M L^2 T^{-2}\,]

Other units

  • joule (J)

Order of magnitude

How values of heat span the physical world (in J, log scale).

Boil a cup of water
7.00 × 104 J
Heat a house (day)
108 J
Lower limit100 JUpper limit109 J

Appears in 3 equations

First Law of Thermodynamics
ΔU=Q−W\Delta U = Q - W
Entropy Change
ΔS=QT\Delta S = \dfrac{Q}{T}
Heat Transfer
Q=C ΔTQ = C \, \Delta T

Associated scientists

Sadi CarnotJames Prescott JouleLudwig Boltzmann