Category: The Quantum of Action

Though it wasn’t fully recognized during Planck’s time, his quantum hypotheses can be generalized beyond oscillating charges in blackbodies to any oscillating system, be it a little girl on a backyard swing, a sloshing wave of seawater, or a retired thrill-seeker dangling from a bungee cord. In contrast to our artificial “quantum staircase” from the…

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.…

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…

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…

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…

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…