Quantum mechanics arose from Planck's answer to the black-body radiation problem.
 These early attempts to understand microscopic phenomena, now known as the "old quantum theory", led to the full development of quantum mechanics in the mid-1920s by Niels Bohr, Erwin Schrdinger, Werner Heisenberg, Max Born, Paul Dirac and others
 Einstein further developed this idea to show that an electromagnetic wave such as light could also be described as a particle (later called the photon), with a discrete amount of energy that depends on its frequency

