Talks and notes
Here are the notes from a couple of informal talks I've given. One might imagine that, given the vastness of the internet, it's worthwhile putting these up as someone might find them useful or interesting. We'll see!
Maxwell's hairy balls
The slides from a talk given in an informal internal seminar series. It's about whether a spherical light wave, like you'll find in any introductory optics textbook, really exists. The answer is related to the well-known hairy ball theorem of topology. I also talk a little about the very beautiful Poincare-Hopf theorem. It probably doesn't fully make sense without me droning over the top of it.
Download [3.0MB].
Measurement error and the bootstrap
Some notes for a tutorial-ish talk on a couple of topics in statistics that come up a lot in the lab, but aren't often dealt with well in basic statistics courses. The first topic is that of fitting data where you have uncertainties in both the x- and y-coordinates. I look (a little) at least-square fitting, attenuation correction and orthogonal regression. The second is what to do if your data seem to be coming out with a distribution that isn't Gaussian. Bootstrap, bootstrap, bootstrap!!
Download [1.2MB].
Rockets on strings
A short talk on an interesting, simple problem in special relativity, that of two identical rockets joined by a thin string. It's interesting because the answer isn't obvious, to the extent that people still argue about it in journals. Even though it's pretty clear which the right one is. The real interesting thing though is why people's intuition lets them down, which John Bell argues is due to a flaw in the way special relativity is taught. I made this in a bit of a hurry, so some of it is crufty and unclear, and bits might even be wrong. But it's got some nice quotes in (attribution unhelfully unclear - like I said, in a hurry) and the idea is interesting!
Download [600kB].