My department has lots of international grad students, and they’re all boggled by our strange units of measurement. Inches? Yards? Fluid ounces? Acre-feet?
The metric system is so nice. When you’re working with contaminants, you work on lots of different scales and they’re a cinch to convert. 1 m3 = 1000 L; 1 L = 1000 cm3 (mL), etc etc.
And then you start doing fieldwork, where you have a horrible mishmash of units. For example, you often need to remove x well volumes of water. And you’ve got a 5 gallon bucket to measure your water volume and dump into a 55-gallon drum. And how do you measure flow? In mL/minute! Then you’ve got a well that’s 2 inches in diameter, and has x feet of water in it (measured in tenths of a foot, rather than inches, of course – the need to find measuring tapes/rulers scaled in 10ths of a foot is another pain). Back of the envelope-y calculations are fine, so you start figuring, ok, it has a 1 inch radius, so if you convert it to cm, then square it, then, multiply it by 3.14, then, um…
So you do all the conversions, and if you have a standard 2-inch well, then each foot of water is 0.16 gallons (I think…it’s been a while). Ok, that’s doable, right? And then you find that your site has some odd 1.25 inch temporary wells and then you start calculating all over again.
That’s why there’s always a cheap calculator in my toolkit, along with everything else.