Happy World Metrology Day!

By Hamish Johnston

“A chance to celebrate measurement and precision”, that’s how the BBC’s Sarah Montague introduced an interview this morning with the National Physical Laboratory’s chief scientist John Pethica about World Metrology Day.

On this day in 1875 the “Metre Convention” was signed in Paris by 17 nations. It provides the basis for the international agreement on units of measurement that exists to this day.

While Pethica did his best to explain why we need to agree on standard units, Montague asked him if “people who like pounds and ounces should be sad today?”.

I thought it was rather silly to try to whip up controversy on World Metrology Day — and Pethica didn’t rise to the bait.

Instead he pointed out that regardless of what units are used locally, there should be a universal system of measurement.

That reminded me of the amazing Gimli Glider incident in 1983, when an Air Canada Boeing 767 ran out of fuel in mid-flight. Why? Someone forgot that the airline had just switched from measuring fuel in gallons to litres – yikes!

The crew decided to make an emergency landing on an abandoned airstrip in Manitoba. What they didn’t know is that had been converted into a dragstrip — and there was a race going on.

Amazingly no-one was seriously hurt — but now airlines take fuel metrology very seriously!

And what is NPL doing to mark World Metrology Day? It’s the formal opening of the National Measurement Office at NPL which is putting togehter a “coherent plan” for all measurements.

You can listen to the interview here — you’ll have to scroll down a bit to 0744.