Friday, February 15, 2008
Got any Rules of Thumb?
I’ve had a bunch of jobs over a long and wildly varied life, and have had my professional competence certified by the government in at least two separate careers (and by both Microsoft and Cisco Systems for a third).
I’ve learned many general rules for shortcuts to quick calculation in those careers, such as “a mile is a minute and a minute is a mile” when I was an Operations Specialist. (As any sailor knows, that means that “one nautical mile is approximately equal to one minute of latitude”.) I’m not talking about mnemonics, such as “May I Have A Large Container Of Orange Juice Now?” (the number of letters in the words gives you 3-1-4-1-5-9-2-6-5-3 - the first ten digits of Pi), or even “red sky at morning, sailor take warning, red sky at night, sailor’s delight”, but rules of thumb, where it gives you an answer that is down and dirty, but “good enough” for first approximations.
Another example is switching from Celsius to Fahrenheit. Instead of the unwieldy “divide by five, multiply by nine, then add 32”, you can simply use a handy rule of thumb - double the Celsius reading and add thirty.
So what rules of thumb do you know?
Death of a Legend
Legendary [Loch Ness Monster] hunter Robert Rines is giving up his search for the monster after 37 years ...
Despite having hundreds of sonar contacts over the years, the trail has since gone cold and Rines believes that Nessie may be dead, a victim of global warming.
Up next? Elvis. 
(Via Tim Blair)