Time Zones
I recently wrote this article, appearing in the June 2015 edition of Physics World, in order to try and get to grips with my confusion regarding the world's time zones. The attempt concerns a counterintuitive movement of one's thumb. The underlying physical principle is known, amongst other things, as a Geometric Phase, Hannay Angle, Gauge Connection, or Holonomy/Anholonomy. The Quantum Mechanical equivalent is the Berry Phase.
I would like to thank my friends Georgina Tate, Megan Gimber, and John Hannay for helpful comments on earlier drafts of the article; if you understood how to do the hand movement it is due entirely to their feedback. If you didn't, try reading the excellent and very readable article I learnt the trick from, by Robert Batterman (linked here).
The article can be considered a sequel, of sorts, to my 2014 article about how you can understand certain properties of an electron's spin in terms of a different hand movement (which has its own ‘Fun Extras' page here). At present I am trying to think of a third demonstration in order that I can finish the “Things to do with your right hand” trilogy. Suggestions, tasteful or otherwise, are welcome.