3 ms·

Calibrating slightly less accurate clocks. What those clocks are used for I have no idea, but there’s times you need a good traceable measurement for some calib

by m-ee 6y ago

Calibrating slightly less accurate clocks. What those clocks are used for I have no idea, but there’s times you need a good traceable measurement for some calibration of your own and your uncertainty stack can start to add up. The better, smaller, and cheaper NISTs equipment is the better your local cal lab will be and the easier your work is. Try finding a thermometer setup that’s better than 1 degree accurate from 0-400C. It might be more than you expect. Now imagine you want to measure some property of a sensor or material as function of temperature using your new thermometer, add in the cost of an oil baths and precision multimeters. Now say you want to create your own golden standard with the best precision you can muster, your expensive oil bath is looking lacking and you’re buying Vienna mean standard ocean water...

TooKool4This 6y ago
Well said. The ability to better realize primary standards and disseminate that to secondary metrology labs from national standards is so critical. It’s the same reason I think the work done in changing the SI definition to physical constants is so critical. In a decade or so all secondary labs should have capabilities to measure directly to the definition of a unit without needing to do comparison measurements to national standards. To me it seems like the metrology equivalent of “open sourcing SI units”
- m-ee 6y ago
  It's important work and it can be surprisingly easy to run into the limits of your uncertainty. If you ask someone to measure a temperature in my experience 9/10 times they'll grab a type K thermocouple. Far fewer than 9/10 will tell you that the number they gave you is only guaranteed to be +/-3 degrees. That's good enough for a lot of applications but not all of them, and when something is really critical it helps to understand the full stack if your supplier/lab/coworker is making questionable claims about their accuracy.

by m-ee 6y ago

TooKool4This 6y ago

Well said. The ability to better realize primary standards and disseminate that to secondary metrology labs from national standards is so critical. It’s the same reason I think the work done in changing the SI definition to physical constants is so critical. In a decade or so all secondary labs should have capabilities to measure directly to the definition of a unit without needing to do comparison measurements to national standards. To me it seems like the metrology equivalent of “open sourcing SI units”

m-ee 6y ago
It's important work and it can be surprisingly easy to run into the limits of your uncertainty. If you ask someone to measure a temperature in my experience 9/10 times they'll grab a type K thermocouple. Far fewer than 9/10 will tell you that the number they gave you is only guaranteed to be +/-3 degrees. That's good enough for a lot of applications but not all of them, and when something is really critical it helps to understand the full stack if your supplier/lab/coworker is making questionable claims about their accuracy.