Quantisation of Matter and Radiation - Quantum Physics - Quantization

This video discusses the basic idea of quantisation of matter and radiation. The fundamental base to understanding quantum mechanics is the idea of quantisation. The observable universe is filled with matter and radiation. The atomisation of matter had been a long known concept at least since the times of early Greek philosophers such as Democritus and Leucippus. By the late 19th century, efforts were on to study the atomic origins of matter. J.J. Thomson's discovery of the electron and Millikan's measurement of its charge accurately led to the understanding of charge quantisation. But the exact understanding of atom and its constituents took a few more years. Thanks to the works of the likes of Rutherford and Bohr, a basic atomic model was achieved before further refinements could be made with the development of quantum mechanics. The idea of quantisation of angular momentum was a result of these efforts. The question ever since this development has been about the ultimate building blocks of matter. Quarks and leptons seem to be the ultimate building blocks of matter as per our present understanding.

Another significant advancement around the early 20th century was the discovery of quantisation of energy itself. This was due to the effort of Max Planck who is regarded as the originator of the quantum theory. Planck while trying to explain the blackbody radiation spectrum came up with a brilliant theory that the energy exchanged between the oscillators which make up the blackbody is quantised. The energy of these oscillators was linked to their oscillation frequency. This was a remarkable achievement of human thought. Einstein significantly added to this by trying to explain the photoelectric effect using the then novel quantum theory. That was a stroke of genius. Millikan again got involved when he could prove Einstein's photoelectric theory by deriving Planck's constant using the photoelectric experiment. Thus mankind got to know the quantisation of both matter and radiation. This understanding led to the birth of Quantum Mechanics.