Thursday, December 4, 2014

What I learned on the Mayflower 2

Took the kids and some out of town visitors to Plimoth plantation and the re-creation of the Mayflower (the Mayflower 2).  While onboard, one particularly good actor/guide was in character as a seaman from the 1600's and he explained to us that the modern day unit of time of seconds and minutes came first from navigating distance on the globe. Now, I have been telling students for years about the Babylonians and their base 60 numbering system and how all the units of time come from astronomy, but this little gem escaped me.

The 360 degree circle that a line of latitude or longitude is divided into was not accurate enough, so Ptolemy subdivided each degree into partes minutae primae which were further subdivided into  partes minutae secundae! Argh!  How could I have never noticed that seconds are the second partition and that minutes are related to minutiae ??  Also, I had assumed that the division of time into minutes and seconds were the inspiration for divvying up of degrees in an angle into the same units when it was precisely the opposite!

http://www.scientificamerican.com/article/experts-time-division-days-hours-minutes/
from http://www.edc.uri.edu/nrs/classes/nrs409509/Lectures/4MapBasics/Map_Basics.htm

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