Temperature Units and US Constitution

[ValeryOchkov]

There was again the question about Temperature units 

I will tell one story.

Ten years ago, I was in the city Boulder (Colorado, USA) in NIST and gave a talk about my program WaterSteamPro.

They gave me the NIST handbook on the properties of water and steam. I leafed through it and saw that in units of thermal conductivity a degree of Fahrenheit, not a degree of Rankine. I said that in the old world and in Russia we have were not a wrong degree of Celsius, but correct kelvins.

They told me that it’s easier to change the US constitution than to force American engineers to use here the right degrees of Rankine, and not degrees of Fahrenheit!

But the most surprising was that in this Reference book in units of entropy and heat capacity were degrees Rankine, not Fahrenheit.

[Fred_Kohlhepp]

I was in college (learning to be an engineer) when the push to introduce metric units (the MKS system) was being debated in the US; a large number of people favored this--enough to get us part way converted and create a lot of confusion.  My professors all were in favor of this conversion, so I was taught using the metric system, acceleration from gravity was 9.8.

After graduating I was thrust into the real world, populated by managers and senior engineers who had spent there entire professional lives using english units of measure.  One of these ranted that he did not understand why we had to begin using kilograms of force-- he could see no reason to change.  

The federal government eventually began requiring metric units to be used in all government contracts.  At the time the weight of the helicopter my company was working on was being tracked in the old (english unit) weights and balance computer system.  The company wrote a quick program to switch form english to MKS units.  There was enormous concern and confusion when the total aircraft tabulated weight increased about 50 kg more than the converted tabulated weight in pounds.  (Until someone remembered rounding errors.)

[ValeryOchkov]

I think the most famous error story when converting units is that:

Gimli Glider 

[ValeryOchkov]

[Fred_Kohlhepp]

That was a good one!

Don't forget the NASA Mars orbiter issue

https://mars.nasa.gov/msp98/news/mco991110.html

[tietjee]

I think we all have incidents with unit conversions.  My was in a model basin in Cork.  We were comparing two loads cells for testing.  The engineer I was working with compared the two load cell using the supplied data sheet.  One was in kg and the other was in Newton.  Both were made in Europe.  So much for the metric system. 

[ValeryOchkov]

Sorry,

kg - mass

newton - force

May by kgf or newtonm?

[tietjee]

I know the difference even the conversion.  It was just how casually it was used.  We do the same with lb, lbm, and lbf.

Cheers

[ValeryOchkov]

There was such a PC “Wang-2200”. An interpreter of the BASIC programming language was sewn into it.

By default, this computer started up, set to angular degrees. But after executing the SELECT R or SELECT G operator in BASIC, the calculations were carried out in radians (R) or in grad (G).

There was such a joke. The programmer turned away, and someone replaced degrees with grad. If the replacement were for radians, then the catch would be immediately noticed. But grad do not differ much from degrees - you can create a calculation, but do not feel the substitution until the answer seems strange.

[tietjee]

Your showing your age.  I used a wang while in college, 50 years ago.

[ValeryOchkov]

Soviet Wang-2200 (Iskra-1256) - my first love!

[Fred_Kohlhepp]

Tandy Radio Shack TRS-80 Model 1.  The first home desktop in the USA.

Note that it used a tape cassette recorder for storage.  (Disk drives came later.)

[ValeryOchkov]

Once I sat with my American colleague at an American airport and there was nothing to do (we were expecting our flight), we began to discuss the transition in US aviation from British units to SI. My colleague said that if someone somewhere sees British units at the airport and informs the airport administration about it, he will receive a big bonus. As we walked toward the plane, I saw a height mark on the gate, not in meters, but in feet and inches. I showed it to my colleague. He said that this is the only exception to the rule and they do not give a bonus for it!