Author: haroonkhan
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Trombones, Trumpets, and Triples
Before we go into that, though, it’s worth exploring Planck’s hypotheses and their implications a little bit further. As we will see over the course, blackbody radiation is not the only case where energies are restricted to certain, discrete levels. This concept shows up over and over again in the wacky world of quantum physics.…
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Planck’s Hypotheses
To arrive at his result, Planck followed many of the same steps, which we described above, that other physicists had taken. He, too, assumed the emitted radiation came from thermally excited charges, each oscillating at a particular frequency. In addition, he assumed that the energy emitted at any particular frequency was given by the number…
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Catastrophe Averted
Just as this controversy was heating up, a revolutionary solution was found by a German physicist named Max Planck. One Sunday afternoon in 1900, he was entertaining a fellow physicist named Heinrich Rubens at his Berlin home. A highly accomplished experimenter, Rubens spent the afternoon explaining some of his most recent measurements and how they…
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The Ultraviolet Catastrophe
We mentioned that one of the few electromagnetic phenomena that was not nicely explained by Maxwell’s classical equations had to do with heated solid materials. What exactly was the problem, and how serious was it? Let’s return to our humble fireplace poker to see. First, we need a little bit of terminology. The fancy scientific…
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Introduction
We pull at one of the loose threads that emerged and in so doing unravel the fabric of classical physics. We will see that despite classical physicists’ ability to explain and predict many extraordinary things, they were utterly incapable of explaining why fireplace pokers glowed as they did. We will meet Max Planck, a true…
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The End of Physics?
By the turn of the twentieth century, classical physics had racked up a very impressive series of accomplishments. Newton’s laws of motion could successfully predict the mechanics of all macroscopic bodies. When these laws were combined with his theory of gravity, all of celestial mechanics could be described with tremendous precision. The principles of electricity…
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The Nuclear Model
Imagine you visit an old Civil War fort and observe the ceremonial firing of its cannons, and consider this question: if one were to stretch a large sheet of tissue paper across the cannon’s path, what are the chances a fired cannon ball would bounce off the paper rather than simply tear through? Impossible, right?…
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The Plum Pudding Model
Although his discovery would provide the basis for every piece of electronics in our modern households, Thomson was not satisfied to stop there. Instead, he wanted to understand how exactly the electron fit into the atom’s structure. He surmised that the atom was a small sphere of matter, with a positive charge distributed uniformly throughout,…
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The Divisible Atom?
In the spring of 1889, the World’s Fair opened in Paris in the shadow of the newly-built Eiffel Tower. Six years later, while his fellow Parisians were still craning their necks to study this architectural marvel, the physicist Henri Bequerel was sitting across town, in a darkened room, wrapping rocks in paper. He was studying…
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X-Ray Crystallography
A number of subsequent experiments have proven this early estimate for the atom’s size to be amazingly accurate. One of the more elegant of these was conducted in Munich in 1912 by Max von Laue. Here, he and his students combined the wave theory of light with the concept of the atom to develop a…