For 21 Years, No-One In Britain Knew How Long An Inch Was

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Tom holding up a Subway sandwich up to the imperial yard plaque was a lot more satisfying than I thought it would be.

👍︎︎ 92 👤︎︎ u/Abomm 📅︎︎ Jul 27 2020 🗫︎ replies

If you wanna see what 12 inches looks like....

unzips

It’s six of these.

👍︎︎ 177 👤︎︎ u/Neat_Petite 📅︎︎ Jul 27 2020 🗫︎ replies

Loving Tom's work these days. Just little tidbits of information I wouldn't have ever thought of otherwise.

👍︎︎ 11 👤︎︎ u/insipidwanker 📅︎︎ Jul 27 2020 🗫︎ replies

If you follow the link to his COVID safety precautions he says he lives in a 2m x 5m apartment. What absurd measurements for an apartment!

👍︎︎ 19 👤︎︎ u/Doublecrossedtwice 📅︎︎ Jul 27 2020 🗫︎ replies

The imperial system is now based of metric.

👍︎︎ 23 👤︎︎ u/Terrahurts 📅︎︎ Jul 27 2020 🗫︎ replies

Just watched an episode on the making of medieval castles. Interestingly, every building site would have their own set of measurements that they would use. It was based on someone’s real thumb or real foot. They’d mark it out so everyone on the site could see it, and also in case the person died before construction (a real possibility given major buildings like churches and castles could take decades to finish).

👍︎︎ 6 👤︎︎ u/IrisesAndLilacs 📅︎︎ Jul 28 2020 🗫︎ replies

From the thumbnail I can't tell if this guy is 19 or 59.

👍︎︎ 39 👤︎︎ u/steveoscaro 📅︎︎ Jul 27 2020 🗫︎ replies

Now what sitcom an I remembering where a guy gets a hold of the official inch and shows it off and then smashes it and tries to fix it? Then he's worried about having ruined the official inch, but then they come back and are like you actually made it more precise.

👍︎︎ 3 👤︎︎ u/big_american_tts 📅︎︎ Jul 28 2020 🗫︎ replies

My inch is bigger than your inch.

👍︎︎ 6 👤︎︎ u/soynanyos 📅︎︎ Jul 27 2020 🗫︎ replies
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Great idea, Tom. Film in front of Parliament. It's imposing. It's relevant to the story. It'll look great. It is covered in scaffolding. When you buy a tape measure,  that tape measure had to be   checked and calibrated with equipment at the tape measure factory. And that manufacturing equipment had to be calibrated by other calibration equipment at its factory. And that equipment had to be calibrated, and so on, and so on, and so on, until at some point,  that chain has to stop, there has to be an organisation whose job it is to say: "you don't need to calibrate any  more. Here is the truth." These days, that job's done at the National  Physical Laboratory in the UK, or the National Institute of  Standards and Technology in the US. I've actually been lucky enough to visit both of those in the past, so I'll put links to those  videos at the end of this one. The international standard  for length is the meter, and it's based on unchanging  physical constants: a meter is defined as how far  light travels in a vacuum in   a certain fraction of a second. Is that all in frame? I've got no idea. I can't see my screen. But anyway, ever since the mid-20th century, the international agreement has been that an inch is exactly 25.4 millimetres. Which means yes, the US and imperial  systems of measurement, inches, feet, yards, miles: they're all based on metric now. But before all those  modern standards were set, those systems of measurement  were based on prototypes. Not 'prototypes' as in  'early test versions', but as in physical artifacts  which were, by definition, the length they said they were. "The metre" was the distance  between two marks on a   platinum-iridium bar stored in Paris. If those marks somehow changed, then the definition of the  metre changed with them. Before we went metric, Britain  had physical standards for the   old imperial units, too,  dating back centuries. There are references to various  standards all through history,   but as far as I could tell, the first prototype that could reasonably be called a British national standard was a brass rod that was created in 1760. That standard was eventually  set in law: in 1825, the yard, so three feet, 36 inches, was defined   as being the distance between  the marks on that one object, stored with the Clerk of the  House of Commons, in Parliament. Nine years after that law was passed... Parliament burned down. They were trying to burn old records  that were on wooden "tally-sticks", and the fire got out of control. That famous Parliament building, the one that's behind the scaffolding, it isn't some ancient castle: heck, the US Capitol Building is  older than what's behind there. Only a few parts from medieval  times are still standing: the rest was built during Queen  Victoria's reign, after the fire. Anyway, all the standards  for imperial units were also destroyed in that fire. The ‘standard Yard’  had been partly melted. Which meant Britain didn't have  any legal standard of measurement. But that was fine! Because  the law also had a provision   for what to do in that case:  you make a new Standard Yard, defined by the length of a pendulum that  takes a certain amount of time to swing. Great idea. More than a century early, they were defining the measurements by  physical constants! Just one problem: those definitions were wrong.  Or as the law later put it, "by the Researches of scientific Men  Doubts were thrown on the Accuracy". Those Scientific Men were  the Standards Commission, headed by Astronomer and  Mathematician Sir George Airy. That commission was in charge of  re-establishing the lost units, and their final report made it clear: the government had put a  dodgy experiment into law. It wasn't accurate enough. So instead, the standard was reconstructed  based on all the copies and   other versions that had  been made over all the years, all the objects, not like tape measures, or anything like that, but the things that were one step  down that chain of calibration. So by 1855, a new physical yard had  been constructed, made of bronze, and the law was changed  to define the idea of a   "yard" as the distance between  two gold studs on that new bar. There were a few other suggestions  in the commission's report: they strongly argued for the decimalisation of units and currency, which wasn't successful for a century. But they also said that there should be a public version of the standards in every large town: not because they'd be  perfectly accurate, but because it would make it really really obvious if a shopkeeper with a dodgy tape  measure was trying to cheat you. Those standards still exist  in a few places. In London, you can find them in Trafalgar Square, in the Guildhall, and by the gate of  the Royal Observatory. So if you have bought lunch from, let's say, a certain shop and want to check if your "footlong sandwich" really  is a foot long, you can do that. And I did. So: was the new yard the same  distance as the old one? Well, it would be difficult to  mess it up too much, there were a lot of copies  of the original to work from. But every time you make an  analogue copy of something, you do lose a little bit of precision. Before the 1834 fire, the yard was the  length of one particular block of metal; after 1855, it was the length of  another block. In between: well, you could take a pretty accurate guess, but that chain of calibration,  that source of truth, was broken. For twenty-one years: no-one knew how long a yard, a foot, or an inch actually was.
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Channel: Tom Scott
Views: 1,342,359
Rating: 4.9788156 out of 5
Keywords: tom scott, tomscott, measurement, metrology, things you might not know
Id: mmh819Lfgfs
Channel Id: undefined
Length: 5min 5sec (305 seconds)
Published: Mon Jul 27 2020
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