Last week I stayed late to give a tour of our clock facility, and to show off the fountain, to some brass that were visiting. For me, tours like this are a little bit stressful, because this was more than just the gee-whiz—aren’t—we—cool tour (and tabletop-ish atomic physics makes for some pretty good gee-whiz) we give to some visitors. For those visitors, talking about physics is sufficient, and I’m pretty good at bringing the geek. For visitors who actually have a stake in what we do, I’m trying to make the presentation relevant to the job they do, above and beyond the “timing = navigation, because a nanosecond is a foot.” And really there is more to that message, because timing is also tied in with communication (and more importantly, secure communication) but because I’m the redundant backup for such tours, I don’t have a lot of practice at the high-level discussions. Which makes a feedback loop — because I don’t have a lot of practice to polish the talk (and I’m further down the chain), I don’t get called on to do this often, etc., etc. Iterate.

But things went well enough, and as the admiral shook my hand and thanked me, a coin was transferred into my possession. Challenge coins are a military tradition, that admit I had no awareness of when I was a junior officer in the navy, mostly because they are generally (or admirally) exchanged only when rubbing elbows with top brass of some sort. Wikipedia tells me the tradition probably dates back to WWI. There are coins that reflects one’s unit, and coins that reflect one’s job, especially if one has a job with a large degree of specialization. These are used as identification, and as with so many military traditions, they are often tied into drinking — if challenged to produce your coin and you don’t have it (or sometimes if you are the last one to do so), you are expected to get a round of drinks.

There are other coins that represent one’s command, and still others that are personal coins which will declare the rank of the giver. These can also be presented as a challenge when you’re sitting in a bar, with the owner of the coin representing the highest rank winning, and exempt from having to pay for drinks. The coin I got represents the Admiral’s office at the Joint Chiefs, rather than being a personal coin, so it does not show the rank of Rear Admiral (two stars). The frequency at which one gives out a coin is really a personal decision; I’ve read of flag officers who carried (or, more specifically, had their aids carry) a bag of coins with them because they handed them out so readily, and others who were very stingy. This was my first coin, and was probably given in appreciation for staying fairly late. A true cynic might think this is little different from the kind of cheesy awards you can buy (“You’re a Star” mug, “Celebrate Awesomeness” hunk of plastic or “Team Player” keychain) but I disagree. A coin — especially a nice coin — is not a bulk item, and has a nice tradition behind to back it up. I’m pretty jazzed about it.