It's very frustrating to have both units in America. I wish we would just switch to metric ,it's so much easier! I was just helping my 3rd grader yesterday on homework and he knew 100 C boiling and 0 C for freezing but not 32 and 212 F. What does that tell you?
Maybe that 32F for the freezing point seems a little arbitary or illogical or maybe just a tad archaic?
http://en.wikipedia.org/wiki/Fahrenheit
Using 0degC for the freezing point of water rather than a mixture of brine has some merits. Water is quite important to us. More so than a brine mixture - see link. Below zero and it's ice. Frost, snow, frozen pipes and windscreens are not really convenient. With centigrade or Celsius, negative values are below freezing and positive values are above freezing. Seems simple.
On your more general point about metric being easier, yes it is in my view. Part of this is because the multiples and sub-multiples of units are based on the decimal system. In the electrical field we are all familiar with the unit of power, the Watt, the kW, and the MW. Multiples of 1, 1000, 1,000,000.
For length or distance you have the metre, mm, km etc.
By contrast, a mile is 1,760 yards, 5,280 feet and 63,360 inches.
Pounds, ounces, tons......
But there is more to it than that. The metric (SI) units hang together quite well.
On power, one Volt times one Amp is one Watt. (Note that this is an instantaneous value.)
For Imperial, one HP = 33,000 ft-lb/minute.
One litre of water weighs one kg. A cubic metre is one tonne (metric ton).
The SI unit for energy is the Joule. It is one Watt for one second. Or a force of one Newton for one metre. That ties in mechanical energy and electrical energy.
Or, for power, one Watt is one Nm/s.
Obviously, you can convert using one HP = 746W.
But why would anyone want to if there is an existing integrated systems of units?
