World Metrology Day 2019 - Changes to the SI

In this video celebrating World Metrology Day 2019, Fluke Chief Corporate Metrologist Jeff Gust explains how the measurements we know today are changing to meet the need for more accurate measurements.

Transcript

It happens only about once a generation. The last time it happened was back in 1990 – an event that changes the whole world. All of the technology around us.

As our world continues to innovate, our knowledge of science and technology improves. And when industry drives the need for more accurate measurements, we occasionally need to improve definitions of our measurement system.

In 1990 the volt shift significantly affected the calibration values of our most accurate products. The volt shift was about 9.3 parts per million, which is approximately 100% of the one-year specification of the Fluke 5700 calibrator, one of industry’s most accurate electrical calibration standards.

The magnitude of the change in the volt this time will only be about 0.1 parts per million, which is about a hundred times less than the last redefinition. The only voltage instruments that will be able to detect this change are Fluke products.

This is an incredibly small quantity, but our model 732C is so accurate that even this change is equal to our published calibration uncertainty for this instrument, which is used by nearly every national electrical reference laboratory in the world. The size of this change is equivalent to the width of a human hair, as compared to the length of ten football or soccer fields.

It can affect measurements in medical; it could affect measurements in aircrafts. So it definitely has an effect on any science or field that uses measurements.

What makes this redefinition so special is that we’re changing the definition of mass, expressed by the kilogram, from an artifact that’s enshrined in a special laboratory near Paris to a definition based on constants of nature that are available to all.

I hope that you will also take a few moments to reflect on the importance of measurement in the world we live in and have a happy World Metrology Day.

Recommended Resources:

World Metrology Day Resource Center

New definition of the kilogram (the SI unit of mass) and other SI unit redefinitions in 2019

Recommended Products:

Calibration Instruments