Many scientists have advanced our understanding of the world around us, but perhaps one of the most groundbreaking leaps forward in that understanding took place early in the 20th century. Despite the turmoil in his country, Max Planck’s dedication to his work and his discoveries helped to catapult us into a new era of understanding how sub-atomic particles behave. His work in blackbody radiation was the initial discovery that allowed for the creation of Quantum Physics.
Max Planck was born in 1858 in Kiel, Germany. He spent most of his childhood in Munich after his father received a professorship at the University of Munich, where he taught Law. Planck excelled in his schooling, but not necessarily in Math or Science. Planck was a gifted pianist and considered a career in music, before ultimately choosing to study Physics after being inspired by a Mathematics teacher. (Hoffman 2001, Planck 1920) Planck was successful in his academic career and quickly rose to prominence in his field. He studied under Hermann von Helmholtz and Gustav Kirchhoff, two highly respected men in the physics world who influenced Planck’s interests. He was also influenced by the reading of Rudolf Clausius’ work in thermodynamics and his correction of the first two Laws of Thermodynamics. Plank taught Theoretical Physics at the University of Berlin and continued his research on Thermodynamics and blackbody radiation.
It was in 1900 that Planck published his famous paper: “On the Theory of the Energy Distribution Law of the Normal Spectrum” and in 1918 he received the Nobel Prize in Physics for his work. (Hoffman 2001; Nobel Foundation) In 1930 he was appointed president of the Kaiser Wilhelm Society for the Advancement of the Sciences and maintained this position until 1937. He held this position during Hitler’s rise to power and he worked to keep the sciences free from government intervention, believing that the field should remain objective and separate from those in power. He also worked quietly behind the scenes in order to help scientists who were dismissed from their position due to their religion or open defiance of the Nazi Party. (Hoffman 2001) Planck suffered greatly during the Second World War. His home, possessions, and scientific work were destroyed during a bombing in Berlin.
His son, who was often said to be his best friend and most trusted advisor, was arrested and executed for his involvement in a plot to assassinate Adolf Hitler. Despite all of this, Planck chose to stay in Germany out a feeling of duty to his country. When the Nazi regime fell, Planck took back his post as president of the Kaiser Wilhelm Society during the time of political instability and reconstruction. Despite his advanced age and failing health, Planck continued to work to advance the sciences. He died at the age of 89 in Gottingen in 1947. (Hoffman 2001) Planck’s strongest contribution to the field of Physics is his work on blackbody radiation and the creation of what is known as Planck’s Constant, for which he won the Nobel Prize.
In the late 1800’s physicists in the field of Thermodynamics faced what was known as “The Ultraviolet Catastrophe.” According to the classical model of physics and the Rayleigh-Jeans’ Law, when an object absorbed radiation (such as heat), it emits electro-magnetic radiation. This radiation falls all along the electro-magnetic spectrum, from infrared light to ultraviolet light and gamma rays.
This is why the sun gives off visible light and why if you held a piece of metal over high enough heat, for long enough, it would start to glow red and then white. However, Rayleigh-Jeans’ Law predicts an emission that follows an exponential function that states that the more energy a blackbody or object absorbed (the hotter it gets) the higher the frequency of the radiation it gives off. This would mean that as an object was heated it would start to give off higher and higher levels of ultraviolet light, X-Rays, and gamma radiation. But we know through experimental evidence and general observations that this is not correct. If this were true, our lightbulbs would be giving off a massive amount of gamma radiation and ultraviolet light. While he did not understand at the time the theoretical implications and causes of his work, Planck tried to find a mathematical solution to this problem.
In what he referred to as an “act of desperation”, Planck speculated that rather than energy flowing freely like water in a stream; energy was instead grouped into tiny “packets” that he called quanta. This meant that energy could only travel in these pre-determined amounts. 1 quanta could be emitted in the form of radiation and 1000 quanta could be emitted, but never 1.5 quanta.
Mathematically, this ia shown in the equation E=hf, where E is energy, f represents the frequency of the radiation being emitted, and h is Planck’s Constant which is equal to 6.62607004 × 10-34 m2 kg / s. (Planck 1900) While this does not seem terribly groundbreaking at first, the far reaching implications of this idea created a completely new field that we know as Quantum Mechanics.
This completely changed our understanding of energy. We now know that energy can act as both a particle and a wave, and that their actions can change based on how they are being observed. It forced scientists to create probability models for the outcome of experiments, rather than make a linear assumption based on past results. (Lindly 1996)While Planck did not understand immediately the theoretical repercussions, Albert Einstein used this as a jumping off point for his work on Quantum Theory. Now Planck’s Constant and its use of these “packets of energy” are integral to understanding the Heisenberg Uncertainty Principle, the De Broglie Wavelength, the Schrodinger Equation, Bohr’s model of the movement of electrons in their orbits, and the relationship between the energy and frequency of a photon.
Modern quantum computing is also reliant on these ideas and it is predicted that quantum computing will be the only possible way to power the technology that we are creating. (Beall 2017; Simonite 2017) Planck’s work has been essential to so many theories and leaps in understanding in several fields of study, from physics and astronomy to chemistry and computing. Without his observations, the “ultraviolet catastrophe” would remain unsolved.
Modern computers would lack power and speed. The ramifications of Quantum Mechanics are still being thoroughly explored by physicists today, and their work and so many others, is owed directly back to Max Planck.