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As a metrologist, I am glad of this interest in correct notation, often not enough pondered also among metrologists but essential for understanding with each others. I would say first that any numerical value of an experimental result is always expressed as a rational, not irrational, number, because the number of digits is always bounded by the position of ...


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In short, up until now, the $kg$ was arbitrary, but now people are trying to define it based on universal constants There is a ongoing process to try and link all the units to universal constants. This has been done already for the second (using Cesium) and the meter (using the speed of light in a vacuum) However, the kilogram is a little less ...


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Talking about a "viable" source, we can talk about time, as in how long does it take to go from my place to the grocery store? 10 minutes by bicycle. How long does it take from LA to Boston? 0.04 light seconds, or 4 car hours, or 5 weeks on a boat, etc. So we see that we can use time to define other units, not to mention we really do use time to define many ...


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The duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom. How is this period calculated? The sensor has probably some equations that imply transformations using other units like Kg etc... The number of periods of anything isn't calculated, it's ...


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It's my understanding that the invention of the metric system during the turbulence following the French Revolution also included a switch to decimal time, with ten hours per day, etc., but that it didn't take. There's a certain amount of cultural inertia that has to be overcome; as you're probably aware, those of us in the United States still have many ...


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The French Revolutionary Gov't did try to move towards a decimalized system of time measurement, with a second defined as one-one hundred thousandths of a day (along with decimal hours, minutes and a new calander), around the same time as it introduced the proto-metric system. But unlike the rest of the metric system, the new time keeping system and ...



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