Chemistry and Plank's Constant for Dummies

By the late 1800s, physicists were kind of feeling proud of themselves. They had these fancy theories that could explain all sorts of crazy phenomena, like how planets move and how light refracts when it passes through a glass prism. People even heard that students were being told not to bother with physics as a career because they thought all the big problems had already been figured out.

Back then, people believed that matter and energy were two separate things. Matter was supposed to be made up of tiny particles with mass, and you could pin down exactly where they were in space. On the other hand, energy, like light (which they called electromagnetic radiation), was seen as waves. It didn't have mass and was spread out, so you couldn't really say where it was in space. Plus, they thought matter and light didn't mix at all. Everything they knew before 1900 seemed to fit nicely into this way of thinking.

But with the turn into the 20th century, after lots of more testing, it turns out many of these ideas were completely wrong. The German physicist, Max Plank, saw how things sometimes glow when they get hot enough. He figured out that the things he was observing could not be explained by any rules of that time. It so happened that matter and energy coexist and are directly related, which eventually led to the discovery of Plank's Constant and how changes of energy can be shown in a single equation.