Planck’s hypothesis was postulated by Max Planck for the intensity curve to fit the experimental data which was observed. He then created his formula.Dispite previous attempts to model the experimental data using intensities, Planck's formula allowed energy to be continuously distributed among all frequencies. Planck’s model required that the energy in the atomic vibrations of frequency, f, was some integer times a small, minimum discrete energy.

E_min=hf

Were h is now known as Planck’s constant

h = 6.626176 x 10-34Js

Planck’s proposal, then requires that all the energy in the atomic vibrations with frequency f can be written as

E = nhf

Where n is an integer, n = 1, 2, 3,… no other values of the energy are allowed. The atomic oscillator could not have energy of (2.73)hf or (5/8) hf.

This idea that sometimes the energy can have only certain discrete values is called quantization. We say that the energy is quantized. This is Planck’s quantum hypothesis. “Quantum” means how great or of a fixed size.