"How Planck calculated h and k" -- base units ampere = "ampere" kelvin = "kelvin" kilogram = "kilogram" meter = "meter" second = "second" -- derived units coulomb = ampere second farad = ampere^2 kilogram^(-1) meter^(-2) second^4 joule = kilogram meter^2 second^(-2) volt = ampere^(-1) kilogram meter^2 second^(-3) centimeter = 10^(-2) meter erg = 10^(-7) joule "Kurlbaum measurement" S = 7.31 10^5 erg / (centimeter^2 second) S "Lummer and Pringsheim measurement" lambdam = 0.294 centimeter kelvin lambdam -- calculate c = 299792458 meter / second pi = float(pi) -- use numerical value of pi -- sigma is the Stefan-Boltzmann constant sigma = S / ((373 kelvin)^4 - (273 kelvin)^4) -- E is energy density at theta = 1 E = 4 sigma / c -- R is h/k in Planck's paper R = 4.9651 lambdam / c "Solve for k" k = E (15/8 c^3 / pi^5) R^3 k "Solve for h" h = k R h "Convert base units to joules" k = k "joule" / joule h = h "joule" / joule k h Run