Richard Feynman’s second Messenger Lecture, on the relation between physics and mathematics, is missing no more:

[VIDEO REMOVED FROM GOOGLE’S ARCHIVES]

This is the lecture in which Feynman presents an example I have appropriated before, concerning the necessity of knowing math before being able to do science, and how popularizations of physics often fail because they leave out the mathematics.

Feynman’s example goes like this: I can say that when a planet travels in its orbit, a line from the planet to the Sun sweeps out equal areas in equal times. I can also say that the force pulling on the planet is always directed toward the Sun. Both of these statements require a little math — “equal areas,” “equal times” — but it’s not *really* math, not a kind to give the layman heebie-jeebies. Given some time for elaboration, one could translate both of these statements into “layman language.” However, one *cannot* explain in lay terminology *why the two statements are equivalent.*

The directly relevant part of the lecture starts about twelve minutes in; using a nifty feature of modern Intellectual Property Distribution technology, I’m able to point the Gentle Reader straight to it:

[VIDEO REMOVED FROM GOOGLE’S ARCHIVES]

It was entrancing to watch this the day after I finished Walter Isaacson’s new biography of Einstein. Thanks!

You’re welcome!

I’ve been trading off

SandmanandThe Tale of Genji,so I haven’t had time for the Isaacson book.Thanks for the post, I wasn’t aware of these videos. I thought it would be nice to have all the Feynman Messenger Lectures in one spot in order.

Good idea.

Horray!

On the topic of popularizations of physics, if you’re interested in an example of well-done popularizing (at least I thought it was well-done, ymmv, etc), I’d recommend

Deep Down Thingsby Bruce Schumm. It’s essentially an overview of particle physics starting with basic quantum and special relativity and working up through symmetries, Lie groups and gauge theories, plus a little about beyond-the-SM stuff. He doesn’t shy away from the math too much, but does try to make it accessible to the reader without a deep grounding in the stuff. I read it the summer before my senior year as a physics undergrad and found it interesting and accessible; my father (who got a BS in physics almost 40 years ago and has been an engineer since) found it interesting but got bogged down in the group theory. So definitely at a somewhat higher level mathematically than a lot of popular science writing, but not, I think, inaccessible to the interested layperson who’s willing to put in a little effort. I don’t know how likely you are to find it at your local library, but I’m pretty sure I saw it at the Harvard Coop last time I was in Boston, so it’s probably findable. In case anyone’s curious.Full disclosure: Bruce was my advisor for my undergrad thesis project, but I read the book before I really started working with him, so I think my memories of the book are reasonably unbiased.