Hello, Have a look at the following pages: http://en.wikipedia.org/wiki/Planck http://en.wikipedia.org/wiki/Planck_(disambiguation) You can follow links on those pages too. Bertus

Maybe it will be interesting for you to know: How the Quantum Theory was started ? =. Planck was founder of QT ( quantum of action / energy) Did he discover the quantum experimentally ? No, it wasnt any empirical evidence. Then, what did Planck do? =. Many years Planck was attracted with the absolutely black body problem. If quantum of light falls in an area of absolutely black body and does not radiate back, then " thermal death" comes. In 1900 Planck decided: there is only one way to save the quantum of light from thermal death -- it must radiate with unit: h=Et. This unit doesnt come from any formulas or equations. Planck introduced this unit from heaven, from ceiling. Sorry. Sorry. I must write: Planck introduced this unit (h) intuitively. I must write: Planck introduced unit (h) phenomenologically. =. Many years Planck tried to chance his intuitive discovery into more realistic basis but unsuccessful. =. Socratus =.