The Quantum and Plancks Constant So what is that h that was so important in the Uncertainty Principle? Well, technically speaking, its 6.63 X 10-34 joule-seconds 40. Its call Plancks constant after Max Planck who, in 1900, introduced it in the equation E=hv where E is the energy of each quantum of radiation and v is its frequency41. What this says is that energy is not continuous as everyone had assumed but only comes in certain finite sizes based on Plancks constant. At first physicists thought that this was just a neat mathematical trick Planck used to explain experimental results that did not agree with classical physics. Then, in 1904, Einstein used this idea to explain certain properties of light--he said that light was in fact a particle with energy E=hv 42. After that the idea that energy isnt continuous was taken as a fact of nature - and with amazing results. There was now a reason why electrons were only found in certain energy levels around the nucleus of an atom 43. Ironically, Einstein gave quantum theory the push it needed to become the valid theory it is today, though he would spend the rest of his lift trying to prove that it was not a true description of nature. Also, by combining Plancks constant, the constant of gravity, and the speed of light, it is possible to create a quantum of length (about 10-35 meter) and a quantum of time (about 10-43 sec), called, respectively, Plancks length and Plancks time 44. While saying that energy is not continuous might not be too startling to the average person, since what we commonly think of as energy is not all that well defined anyway, it is startling to say that there are quantities of space and time that cannot be broken up into smaller pieces. Yet it is exactly this that gives nature a finite number of routes to take when an electron interferes with itself. Although it may seem like the idea that energy is quantized is a minor part of quantum physics when compared with ghost electrons and the uncertainty principle, it really is a fundamental statement about nature that caused everything else weve talked about to be discovered. And it is always true. In the strange world of the atom, anything that can be taken for granted is a major step towards an atomic world view.
Posted on: Fri, 25 Oct 2013 07:38:54 +0000
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