[[Thermodynamics MOC]]
# Heat
Heat refers to [[Energy]] in the process of being transferred across the boundary between a [[Thermodynamic system]] and its environment due to a difference in [[Temperature]].
For heat transfer to take place, 
two or more objects must be in [[Thermal contact]].

The flow of heat _into a system_ is given the symbol $Q$.
Hence, $Q$ is positive when the system is colder than its environment.

Heat is closely related to temperature,
but the two are not the same.
See [[The relationship between temperature and heat in a solid or liquid]].
Adding heat can also result in a phase change —
see [[Heat of transformation]].


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#state/tidy | #SemBr