Editing Wien's displacement law (section)

==Criticism==

Marr and Wilkin (2012) contend that the widespread teaching of Wien's displacement law in introductory courses is undesirable, and it would be better replaced by alternate material. They argue that teaching the law is problematic because:
# the Planck curve is too broad for the peak to stand out or be regarded as significant;
# the location of the peak depends on the parameterization, and they cite several sources as concurring that "the designation of any peak of the function is not meaningful and should, therefore, be de-emphasized";
# the law is not used for determining temperatures in actual practice, direct use of the [[Planck's law|Planck function]] being relied upon instead.

They suggest that the average photon energy be presented in place of Wien's displacement law, as being a more physically meaningful indicator of changes that occur with changing temperature. In connection with this, they recommend that the average number of photons per second be discussed in connection with the [[Stefan–Boltzmann law]]. They recommend that the [[Planck's law|Planck spectrum]] be plotted as a "spectral energy density per fractional bandwidth distribution," using a logarithmic scale for the wavelength or frequency.<ref name="Marr2012"/>