The Third law of thermodynamics reference article from the English Wikipedia on 24-Apr-2004 (provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Third law of thermodynamics

The third law of thermodynamics was developed by Walther Nernst and is thus sometimes referred to as Nernst's theorem.

This states that the entropy of a system at zero absolute temperature is a well-defined constant. This is because a system at zero temperature exists in its ground state, so that its entropy is determined only by the degeneracy of the ground state.

A special case of this is systems with a unique ground state, such as crystal lattices. The entropy of these systems as defined by Nernst's theorem is zero (since ln(1) = 0).

See also

• Thermodynamics: Thermodynamic entropy, Timeline of thermodynamics, statistical mechanics, and random processes
• Other: Adiabatic process, Ground state

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