Physics can be defined simply as the study of matter and energy. But that simple definition covers an enormous range of topics.
There’s the classical physics you learned about in high school: It can explain how much force it takes to slide a box across the floor, how heat transfers from one object to another, or how light bends through a prism. Then there are more modern branches, such as particle physics, which seeks to understand the fundamental building blocks of the universe. And physicists are always on the lookout for new branches yet to be discovered (they need something to account for mysteries like dark energy).
All of these topics fall under the umbrella of “physics,” and it’s a lot to keep track of. So here’s some help. In the video below, physicist Dominic Walliman explains how all the subdisciplines of physics are related in one animated “map” of the science.
In the video, Walliman explains a critical truth about physics: As scientists solved mysteries like the laws of motion or electromagnetism, their discoveries opened the door to new mysteries to solve. The mysteries opened by classical physics led to theories on relativity and quantum mechanics. And so on.
As Walliman’s animation shows, there’s still a giant “chasm of ignorance” that scientists are seeking to fill. Even though scientists now know a lot about things like optics, thermodynamics, fluid mechanics, and electromagnetism, their tested theories still can’t explain things like dark matter and dark energy. And there’s no complete theory that squares quantum physics with relativity.
What’s exciting about the “map” of physics, is that even though it is filled up with so many subdisciplines, there may be many, many more to discover.
Walliman has made other great “map” videos, charting the subdisciplines of biology, computer science, chemistry, and mathematics. They’re great, quick, primers that will remind you how much there is to know about the world. Check them out.