metric

Will McGonegal McGonegal.Will at etc.ec.gc.ca
Mon Jun 7 18:19:57 GMT 1999


For anyone interested in the origins of some temperature scales:

http://www.gi.alaska.edu/ScienceForum/ASF13/1317.html

Fahrenheit set the zero point to be a that of a salt, water and ice mixture, 32 as
the freezing point of water and 96 as the temperature of a healthy person -- this was
later adjusted to the currently known value.

As far as the comment that 100F is the boiling point of alcohol, which alcohol would
boil at such a low temperature?  And what mixture of alcohol freezes at 0F?  The
melting point of pure ethanol is -117.3C (-179.14F), boiling point 78.5C (173.3F).
Pure methanol is -93.9C (-137.02F) and 64.96C (148.928F) according to the CRC
Handbook of Chemistry and Physics.

Myself I commonly use both metric and english units and have no problem converting
between the two.  I do much prefer the metric system though as it requires fewer
conversion factors.  The dynamometers that I develop use software that operates in
metric units internally.  Then they are converted to whatever units I need for
display purposes.

Take for instance power.  To get a car of 2000 kg (approx. 4400 lbs) to accelerate at
4 meters per second squared (8.95 mph/s) at a speed (on level ground) of 25
meters/second (55.9 mph) takes 2000 * 4 * 25 = 200000 Watts (200 Kw, or 268.2 Hp).
Much simpler math (less conversion factors) with metric for engineering calculations.




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