The metrology tag has no wiki summary.
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3answers
325 views
Why do we still not have an exact definition for a kilogram?
I read that there is an effort to define a kilogram in terms that can exactly be reproduced in a lab. Why has it taken so long to get this done? It seems this would be fairly important.
Edit
Today I ...
4
votes
4answers
650 views
Measuring the speed of light and defining the metre - absolute or relative?
If the metre is now defined as the distance light travels in vacuum in 1⁄299,792,458th of a second and the speed of light is accepted to be ...
10
votes
6answers
849 views
What's keeping us from simply redefining Avogadro's Number / the Mole as a definite integer?
This might be a question to ask in a Chemistry site, but because there is a lot of talk about redefining many units of measurements in terms of Avogadro's Number / the Mole, I was wondering why we ...
2
votes
1answer
124 views
How do physicists and astronomers handle leap seconds?
I'm confused by the many contradictory descriptions I see about how UTC leap seconds are accounted for. I understand that there are various ways to handle them in common practice, and I've seen a ...
6
votes
5answers
429 views
Why were the SI base quantities chosen as such?
The reasons for choosing length, mass, time, temperature, and amount as base quantities look (at least to me) obvious. What I'm puzzling about is why current (as opposed to resistance, electromotive ...
2
votes
3answers
165 views
What widely recognized organizations set standards used by physics?
I recently answered a question about the meaning of the word "dimension" as used in physics. In that response, I provided the definition given in the International Vocabulary of Metrology (VIM) and ...
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3answers
541 views
Meaning of dimension
I was wondering what dimension can mean in physics?
I know it can mean the dimension of the space and time.
But there is dimensional analysis. How is this dimension related to and different from the ...
