A Quantum Theory for Energy

Planck Quantises Energy!

Planck was surprised to discover that the calculation became unmanageable if the lumps were made infinitely small! He was forced to accept that 'h' could not be zero but had to have a small, but definite, value. Today, 'h' is referred to as the Planck constant and has a value of about 6.63 x 10^-34 Js.

This has a profound consequence – it means that the total energy of the vibrating system of oscillators cannot be changed continuously but rather must change in discrete steps (or 'quanta' – Latin for "how much") dictated by the value of 'h'.

Planck had unveiled a completely new face of Nature! On December 14, 1900 he presented his results to the Berlin Physical Society, heralding the birth of quantum physics. Planck was 42 years old. The idea was so bold and radical that Planck himself was not totally convinced of its validity – he worried that his quanta arose from a mathematical trick and would one day be replaced by something better. In fact, the idea lay fallow for many years while people spent their time with the newly found phenomena of radioactivity and x-rays. Einstein eventually used the concept to explain the photoelectric effect in 1905. Planck was eventually awarded the Nobel Prize in Physics for his work in 1918.

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