Posted by daestrom on December 28, 2008, 8:33 pm
'Round these parts, we call that ice! (unless it's mixed with a lot of road
Posted by ransley on December 29, 2008, 9:11 pm
I should re-read before hitting send, its 35f incomming, sorry.
Posted by Eeyore on December 30, 2008, 12:49 am
Wow 2C ! Better than -6C though. Has it never occurred to you that measuring
temps above the freezing point of water as positive and those below as negative
might make some calculations easier ?
And a 1 metre cube of water weighs a tonne. Nice simple units to use.
Boiling point 100C. Nice simple number.
Posted by Jim Wilkins on December 30, 2008, 12:49 pm
The story I learned was that Fahrenheit chose the freezing point of a
saturated salt solution for zero, to avoid supercooling. He initially
picked body temperature for 100 and later adjusted the scale to make
the freezing point come out even. The idea was that any lab could
duplicate the measurements, which wasn't possible using the boiling
point which he discovered to vary with altitude. http://en.wikipedia.org/wi=
The triple point would be a better definition of 0C, but all of the
original 1790's standards for the metric system were inaccurate
Unlike the kilogram the pound is a unit of force, independent of
gravity. For most practical purposes we can use it as a mass as well
and avoid having two units for functionally the same thing. The
'reaction' force supporting 2000 pounds of water is simply 2000 Lbs,
but for your tonne it's 9800 Newtons.
Posted by Eeyore on December 30, 2008, 9:16 pm
Jim Wilkins wrote:
More like 9810 newtons actually.
The kilogram (or tonne) is a unit of mass. Force is something else entirely.