Editing Talk:2073: Kilogram
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I didn't know that weights and currencies could be converted 1:1, that's cool! [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 16:37, 16 November 2018 (UTC) | I didn't know that weights and currencies could be converted 1:1, that's cool! [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 16:37, 16 November 2018 (UTC) | ||
I wish they ''had'' redefined the kilogram a little bit. It would have been neat if 1 kg was exactly the weight of 1 dm^3 (1 litre) of water under one atmosphere of pressure. Right now it's soooo close. It's a good enough estimate for simple maths, but whenever you tell people that a litre of water weighs one kilogram the pedants comes out of the woodworks... [[User:Kapten-N|Kapten-N]] ([[User talk:Kapten-N|talk]]) 16:50, 16 November 2018 (UTC) | I wish they ''had'' redefined the kilogram a little bit. It would have been neat if 1 kg was exactly the weight of 1 dm^3 (1 litre) of water under one atmosphere of pressure. Right now it's soooo close. It's a good enough estimate for simple maths, but whenever you tell people that a litre of water weighs one kilogram the pedants comes out of the woodworks... [[User:Kapten-N|Kapten-N]] ([[User talk:Kapten-N|talk]]) 16:50, 16 November 2018 (UTC) | ||
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:You'll get pedants whenever you refer to a kilogram as weight; it's a mass. The difference is that stuff weighs less on the Moon - or on tall mountains - although the mass is the same. I think the article as I just read it gets away with this. And, sure, what is the standard kilogram but a weight, that you take and weigh... [email protected] [[Special:Contributions/162.158.91.59|162.158.91.59]] 23:57, 16 November 2018 (UTC) | :You'll get pedants whenever you refer to a kilogram as weight; it's a mass. The difference is that stuff weighs less on the Moon - or on tall mountains - although the mass is the same. I think the article as I just read it gets away with this. And, sure, what is the standard kilogram but a weight, that you take and weigh... [email protected] [[Special:Contributions/162.158.91.59|162.158.91.59]] 23:57, 16 November 2018 (UTC) | ||
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::: No, it doesn't require an environment of precisely 1g, it relies on the fact that the effect of local gravity is well understood, can be measured precisely, and compensated for. It's a fundamental aspect of the Kibble balance and you can rest assured that it hasn't been overlooked by the physicists designing it! [[Special:Contributions/162.158.134.34|162.158.134.34]] 16:38, 17 November 2018 (UTC) | ::: No, it doesn't require an environment of precisely 1g, it relies on the fact that the effect of local gravity is well understood, can be measured precisely, and compensated for. It's a fundamental aspect of the Kibble balance and you can rest assured that it hasn't been overlooked by the physicists designing it! [[Special:Contributions/162.158.134.34|162.158.134.34]] 16:38, 17 November 2018 (UTC) | ||
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Up until 1964 a litre (and therefore actually the metre too) used to be defined as the volume that water with mass 1kg takes. But this is not good for exact measurements not only because you need exactly reproducable temperature, pressure (not so problematic, because you can measure them and then calculate the divergence) and gravity (not so easy to measure, because you need an exact mass and exact masses are impossible to keep the same), but also because you need pure water free of any polutions of other stuff (hard and expensive) and even free of tiny amounts of isotopes which are deuterium and tritium (even way more expensive). | Up until 1964 a litre (and therefore actually the metre too) used to be defined as the volume that water with mass 1kg takes. But this is not good for exact measurements not only because you need exactly reproducable temperature, pressure (not so problematic, because you can measure them and then calculate the divergence) and gravity (not so easy to measure, because you need an exact mass and exact masses are impossible to keep the same), but also because you need pure water free of any polutions of other stuff (hard and expensive) and even free of tiny amounts of isotopes which are deuterium and tritium (even way more expensive). | ||
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:But how do you define/measure a Joule then? [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 18:19, 16 November 2018 (UTC) | :But how do you define/measure a Joule then? [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 18:19, 16 November 2018 (UTC) | ||
:No, until 1964, meter and litre were totally independent, a meter has never been defined directly or indirectly in relation to a mass of water. It is only since 1964 that the liter is defined as a cubic decimeter.[[Special:Contributions/162.158.90.36|162.158.90.36]] 18:36, 16 November 2018 (UTC) | :No, until 1964, meter and litre were totally independent, a meter has never been defined directly or indirectly in relation to a mass of water. It is only since 1964 that the liter is defined as a cubic decimeter.[[Special:Contributions/162.158.90.36|162.158.90.36]] 18:36, 16 November 2018 (UTC) | ||
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:Also, in E=mc², E is the energy '''at rest''' (for a stationary object of mass m), so your definition using the acceleration makes no sense.[[Special:Contributions/162.158.88.254|162.158.88.254]] 18:47, 16 November 2018 (UTC) | :Also, in E=mc², E is the energy '''at rest''' (for a stationary object of mass m), so your definition using the acceleration makes no sense.[[Special:Contributions/162.158.88.254|162.158.88.254]] 18:47, 16 November 2018 (UTC) | ||
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Actually, for the new definition of the kilo using the Kibble balance you need to measure the gravity... [[Special:Contributions/162.158.134.16|162.158.134.16]] 17:34, 16 November 2018 (UTC) | Actually, for the new definition of the kilo using the Kibble balance you need to measure the gravity... [[Special:Contributions/162.158.134.16|162.158.134.16]] 17:34, 16 November 2018 (UTC) | ||
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:::: No longer necessary in modern life... Which is why we should all switch to base-10 units of time! [[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 08:36, 17 November 2018 (UTC) | :::: No longer necessary in modern life... Which is why we should all switch to base-10 units of time! [[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 08:36, 17 November 2018 (UTC) | ||
::::: Or we could change everything else to base 12... (I can dream, can't I?) [[User:Linker|Linker]] ([[User talk:Linker|talk]]) 18:45, 17 November 2018 (UTC) | ::::: Or we could change everything else to base 12... (I can dream, can't I?) [[User:Linker|Linker]] ([[User talk:Linker|talk]]) 18:45, 17 November 2018 (UTC) | ||
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Ok, I'm going to point out something. What's a meter? 1000 milimeters. What's a milimeter? .....skipping the questions all the way to the end, the answer is "the wavelength of the color orange". Or at least that's what I read. So my question is: why orange? What's so special about orange? What as a species or as a solar system or as universe does the color orange have to do with anything? [[Special:Contributions/172.68.90.10|172.68.90.10]] 21:50, 16 November 2018 (UTC) SiliconWolf | Ok, I'm going to point out something. What's a meter? 1000 milimeters. What's a milimeter? .....skipping the questions all the way to the end, the answer is "the wavelength of the color orange". Or at least that's what I read. So my question is: why orange? What's so special about orange? What as a species or as a solar system or as universe does the color orange have to do with anything? [[Special:Contributions/172.68.90.10|172.68.90.10]] 21:50, 16 November 2018 (UTC) SiliconWolf | ||
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: "The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole." That's why orange. Think of those lines from equator to pole... and how an orange is divided in segments beneath the peel. This is why the "Terry's Chocolate Orange" is so called, because it resembles the fruit orange. [email protected] [[Special:Contributions/162.158.91.59|162.158.91.59]] 23:51, 16 November 2018 (UTC) | : "The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole." That's why orange. Think of those lines from equator to pole... and how an orange is divided in segments beneath the peel. This is why the "Terry's Chocolate Orange" is so called, because it resembles the fruit orange. [email protected] [[Special:Contributions/162.158.91.59|162.158.91.59]] 23:51, 16 November 2018 (UTC) | ||
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:I feel like we're starting to compare angstroms & millitrumps, here. [[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 08:36, 17 November 2018 (UTC) | :I feel like we're starting to compare angstroms & millitrumps, here. [[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 08:36, 17 November 2018 (UTC) | ||
::I don't think we need to bring politics in here. [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 15:16, 19 November 2018 (UTC) | ::I don't think we need to bring politics in here. [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 15:16, 19 November 2018 (UTC) | ||
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While it would be nice if the meter were equal to a yard, it would certainly be better if the meter were defined as 5.28 feet, so that kilometers and miles are the same.[[User:Mathmannix|Mathmannix]] ([[User talk:Mathmannix|talk]]) 13:54, 17 November 2018 (UTC) | While it would be nice if the meter were equal to a yard, it would certainly be better if the meter were defined as 5.28 feet, so that kilometers and miles are the same.[[User:Mathmannix|Mathmannix]] ([[User talk:Mathmannix|talk]]) 13:54, 17 November 2018 (UTC) | ||
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I'm guessing that they'll get around the varying g problem by defining the kg in terms of some standard acceleration equal to 9.81 m/s^2. Then when measuring an object's mass you would account for the difference between the local value of g and the standard one. This isnt a problem because we can measure gravitational acceleration quite precisely and it depends only on the units of length and time. | I'm guessing that they'll get around the varying g problem by defining the kg in terms of some standard acceleration equal to 9.81 m/s^2. Then when measuring an object's mass you would account for the difference between the local value of g and the standard one. This isnt a problem because we can measure gravitational acceleration quite precisely and it depends only on the units of length and time. | ||
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There is already one link to a Veritasium video on this subject a few coments above, and there was a new video out just before this vote, about the new units: [https://www.youtube.com/watch?v=c_e1wITe_ig The kg is dead, long live the kg]. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 15:57, 19 November 2018 (UTC) | There is already one link to a Veritasium video on this subject a few coments above, and there was a new video out just before this vote, about the new units: [https://www.youtube.com/watch?v=c_e1wITe_ig The kg is dead, long live the kg]. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 15:57, 19 November 2018 (UTC) | ||
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