- #1
elPhys
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Some sources say it's held in a double-bell jar while others say it's a triple-bell jar. What's the scoop?
Kilogram in France: Double-Bell or Triple-Bell Jar?
- Thread starter elPhys
- Start date
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Discussion Overview
The discussion revolves around the physical containment of the kilogram prototype in France, specifically whether it is held in a double-bell jar or a triple-bell jar. Participants explore historical context, visual evidence, and differing interpretations of the prototype's presentation.
Discussion Character
- Debate/contested
Main Points Raised
- Some participants note conflicting sources regarding whether the kilogram is housed in a double-bell jar or a triple-bell jar.
- One participant references a photo from the BIPM website as evidence for the current containment method.
- Another participant cites the third edition of Halliday and Resnick, which depicts the kilogram in what appears to be a double-bell jar, raising questions about historical changes in its containment.
- There is speculation about whether the outer jar is considered a true bell jar, given its lack of a knob, and whether the Halliday and Resnick image focuses only on the inner jars.
- A participant expresses a humorous sentiment about the kilogram, suggesting a desire for its liberation.
Areas of Agreement / Disagreement
Participants do not reach a consensus on whether the kilogram is in a double-bell or triple-bell jar, indicating multiple competing views and unresolved historical context.
Contextual Notes
The discussion highlights potential limitations in the sources referenced, including the ambiguity of visual evidence and the definitions of what constitutes a bell jar.
- #2
f95toli
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There is a photo on the BIPM website, so see for yourself
http://www.bipm.org/en/scientific/mass/pictures_mass/prototype.html
http://www.bipm.org/en/scientific/mass/pictures_mass/prototype.html
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- #3
elPhys
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But in the third edition of Halliday and Resnick it shows a picture of it in what appears to be a double bell jar.
So is there some history I'm missing? Was it originally in a double bell jar and then another bell jar added later?
Or maybe the outer "bell jar" isn't considered by some to be a true bell jar (since it doesn't have a knob at the top), and the Halliday and Resnick photo was zoomed into take a picture of just the inner two jars?
So is there some history I'm missing? Was it originally in a double bell jar and then another bell jar added later?
Or maybe the outer "bell jar" isn't considered by some to be a true bell jar (since it doesn't have a knob at the top), and the Halliday and Resnick photo was zoomed into take a picture of just the inner two jars?
- #4
lisab
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Free the kilogram! Free the kilogram!11!
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