Conversions

 I've worked as a chemist for more than four decades. Over that time the technology I've used has shifted from punch cards to magnetic tape to solid state storage to the cloud. I once encoded molecular structures using something called a Z-matrix, now I sketch them on a screen. I began using log tables and a slide rule to do calculations, and can now pull up something on my phone to do weird fractional roots while on a walk.¹ 

But this reference card I made my first semester as a graduate student has been the one constant in all that changing technology. It sat on my desk as a grad student and again when I was a post-doc. It was pinned to the bulletin board behind my desk in my old office. When I moved offices it took up residence in the small bin on my desk.

So I was distressed when I couldn't locate it yesterday. I was back in my office at the college, looking for the card to use to illustrate an essay about units and their names. My office is torn apart, as I was invaded by mice during the pandemic. I had to pull several hundred books off their shelves, and many of these are still stacked on the floor and on my working table. I reached for the bin and...no card! My heart sank. 

I looked all over. Had I inadvertently used it to mark a page in a book while talking to a student? Left it by the chalkboard? Taken it down to the lab? No, no and no. I finally concluded I must have mistakenly tossed it with the mouse infested papers from my desk. I was surprisingly saddened by this loss of the one artifact that threads through my entire career. 

Truth be told, I don't need this card. The values are readily available in many places online and off. I rarely refer to it. After all these years, the conversion factors I use regularly are in my head, I can flip effortlessly between Ångstroms and bohrs and nanometers. And the handy conversion between angles inscribed at the top? I can't recall the last time I used it, since relative coordinates have gone the way of the dodo. But there was an ineffable sense of loss nonetheless.

I headed home, and on a whim, checked the bin on my desk. There was the card, ready to be consulted. When I grabbed the essentials from my office back in March, I had taken this not-really-essential essential. I guess I don't have to retire just yet.

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Notes:

1. Math Man was mulling about his research on our daily walk, trying to work out a 2/3 root in his head, which we did, but then I offered to check it on the phone. Our estimate was just fine!