Course Report: A Brief History of Timekeeping 04

Through a weird quirk of scheduling, I haven’t actually taught the intro modern physics course since I started writing pop-science books about modern physics. So, this week has been the first chance I’ve really had to use material I generated for the books to introduce topics in class.

In the approximately chronological ordering of the course, we’re now up to the late 1800’s, and the next book we’re talking about is Einstein’s Clocks, Poincar$eacute;’s Maps, which talks about how Einstein and Henri Poincaré were (arguably) influenced by developments in timekeeping as they looked for the theory that became Special Relativity.

This is a much more academic book than the previous readings, and as such has really long chapters and sections. To space things out a little bit (giving them more time to read), and to give them a better idea of what relativity is about (which I think is helpful when reading Galison’s discussion), I’ve spent the last two classes talking about relativity. Monday’s lecture introduced Special Relativity and spacetime, and today’s lecture introduced the Equivalence Principle and general relativity. Those slides are a little short on words because I was largely copying figures from the book, and because I’m trying to generate less wordy PowerPoints as a general matter. They should give you the right basic idea, though, and if you want more explanation, well, you can pre-order How to Teach Relativity to Your Dog (or enter our Photoshop contest)…

The other development of the week is that I’ve been meeting with students about final project topics. I wrote the requirements to be very vague, leaving open the possibility of making or measuring something, but they’re mostly choosing fairly traditional research-paper topics. Which is probably to be expected, given the chronological organization of the course– we’ve primarily been talking about historical topics to this point, so most of the passing references that might’ve suggested themselves as good paper topics have been to old stuff that you can read about in books.

For the most part, they’ve had reasonable ideas, though, so I’m hopeful that the final products will be good. We’ll see.

So, that’s where the class is, and where I’ve been at mentally for the last week or so. On Friday, we’ll actually start talking about Galison’s book, and how Poincaré approached the question of time.

1 comment

  1. In your slides for the introduction to special relativity, you state that Eintein’s 1905 paper on the topic of “One of four incredibly important papers that year by Einstein.” It doesn’t hurt to point out exactly what those papers were, and why they were so important:

    1. A. Einstein, “Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt” (“On a heuristic point of view concerning the production and transformation of light”), Annalen der Physik 17 (1905) 132-148 (in which Einstein explains the photoelectric effect)

    2. Einstein, Albert (1905). ”Über die von der molekularkinetischen Theorie der Wärme geforderte Bewegung von in ruhenden Flüssigkeiten suspendierten Teilchen” (“Investigations on the theory of Brownian Movement”). Annalen der Physik 17: 549–560. (in which Einstein used an analysis of Brownian Motion to prove John Dalton’s Atomic Theory of Matter)

    3. Einstein, Albert (1905-06-30). ”Zur Elektrodynamik bewegter Körper” (“On the Electrodynamics of Moving Bodies”). Annalen der Physik 17: 891–921. (The Special Theory of Relativity)

    4. Einstein, Albert (1905). ”Ist die Trägheit eines Körpers von seinem Energieinhalt abhängig?” (“Does the Inertia of a Body Depend Upon Its Energy Content?”). Annalen der Physik 18: 639–641 (Mass-energy equivalence in Special Relativity)

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