Saturday, November 20, 2010

Calibrated pace

kw: measurements, walking, animals

During a walk today, I decided to re-calibrate my pace. The schoolyard running track was gravel until recently, when they put on one of the new rubberized, permanently marked tracks. Decades ago I calibrated my pace on a quarter-mile track with good markings at 5.6 feet, or 1.71m. That is also 942 paces to the mile.

Modern tracks are all in meters. It took 62 paces to go 100 meters, and both trials I measured, my last pace went long about 10 cm. So 100.1/62 comes to 1.615m or 5.3 feet; 997 paces to the mile. This is where the mile gets it name: mille pas or "thousand paces".

I first calibrated my pace as part of a field mapping class, when I was a Geology undergraduate. While we did most of our mapping exercises using an alidade (a calibrated telescope, but primitive compared to a theolodite) and plane table, we had to do a few the Boy Scout way, using a compass and pacing to get bearings and distances.

A steady pace works well enough on flat ground, but we soon learned how much it varies when the ground gets hilly, and of course much of our work was done in a cliffy area where pacing distances just wasn't an option. Triangulation from a well-measured base line provides the most accurate survey.

Update on our mouse problems (see This mouse got away): I checked the rat-size glue trap for a couple of days, then not until today. It contained a very dead mouse. I felt bad that I didn't find it in time to put him out of his misery quicker. But we thought he wasn't there; we saw a mouse in the garage the day after I wrote that post, and that one we caught with a snap trap. I put a new glue trap in the crawl space, in case they still have a way to get in. If I keep catching mice there, I'll have to go in again and see if there are holes to fill I missed the first time.

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