The Black Body Radiation Paradox by Max Planck

Max Planck didn't actually propose that light really was quantized he just sort of said well this is a useful mathematical technique that we can apply to solve the black body radiation paradox but you know we don't have to take it too seriously. Max's theory required that so-called atomic oscillators could only vibrate at certain discrete energies which would mean they would only emit light in tiny discrete bundles called quanta. According to planks Max Planks equation higher frequencies of radiation meant more energetic quanta and with higher frequencies translates to more energy.