Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Max Planck originally produced this law in 1900 in an attempt to improve upon the Wien approximation, published in 1896 by Wilhelm Wien, which fit the experimental data at short wavelengths but deviated from it at long wavelengths. The Rayleigh-Jeans law fit well in the complementary domain. Planck found that the above function, Planck''s function, fitted the data for all wavelengths remarkably well. In constructing a derivation of this law, he considered the possible ways of distributing electromagnetic energy over the different modes of charged oscillators in matter.