I first learned as a kid that “there are only 17 basically different wallpapers” from W.W.Sawyer’s Prelude to Mathematics. (The quote appears on p.102. Aside: this remains an excellent gift for a youngster with a yen for math.) I remember my father pointing out the absurdity of this claim: are all mural wallpapers of van Gogh’s paintings basically the same?

# Category Archives: Physics

## Epstein Relativity Diagrams

[This post is available in pdf format, sized for small and medium screens.]

Lewis Carroll Epstein wrote a book *Relativity Visualized*. It’s been called “the gold nugget of relativity books”. I wouldn’t go quite *that* far, but Epstein has devised a completely new way to explain relativity. The key concept: the Epstein diagram. (I should mention that *Relativity Visualized* is a pop-sci treatment.)

## Why “atomic bomb” instead of “nuclear”?

Why do we (mostly) say *atomic bomb* instead of *nuclear bomb*, which is technically more correct? This was asked on the History of Science and Math stackexchange. Here’s my answer.