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Everything is getting heavier

wired.com

1–10 of 29 posts

Re: Everything is getting heavier

#3

A fabulously overwrought drama of no value. Similar to Tibetan rituals. Other standards are related to fundamental physical constants. Time for weight to do the same.

The article makes it quite clear why it isn't possible to relate weight to fundamental physical constants yet: the constants that can be used for this haven't been measured precisely enough yet. Until they are, using a block of metal in a vault that has lost about half a speck of dust worth of matter in two hundred years is more exact.

[edit: typo]

Re: Everything is getting heavier

#4
Editorialised title - actual title is "The Search for a More Perfect Kilogram". Wired should use your title though ("Everything is Getting Heavier") - it's a catchy title for an interesting article. Also the picture half-way down is totally a TARDIS.

Re: Everything is getting heavier

#7
Can somebody (preferrably, a physicist or a chemist) explain to me two things.

1. Why do we need both kilogram and mole as fundamental units when they measure essentially the same thing (at least in case when the thing being measured is pure)?

2. Why not reverse the definition: postulate that 1 mole is Avogadro's number of elementary particles; 1 mole of C-12 has 12 grams and derive (kilo)gram from that.

Re: Everything is getting heavier

#8
Huh?

"In fact, of the seven fundamental metric units — the kilogram, meter, second, ampere, kelvin, mole, and candela — only the kilogram is still dependent on a physical artifact."

Followed by:

"And the luminosity of light, or candela, is measured in terms of power, designated in watts, or joules per second."

I'm not an SI expert, but Wikipedia suggests the candela is in fact an SI base unit with a definition based on physical phenomenon of the universe, so the second sentence seems erroneous.

[edit: clarity]

Re: Everything is getting heavier

#10

Huh? "In fact, of the seven fundamental metric units — the kilogram, meter, second, ampere, kelvin, mole, and candela — only the kilogram is still dependent on a physical artifact." Followed by: "And the luminosity of light, or candela, is measured in terms of power, designated in watts, or joules per second." I'm not an SI expert, but Wikipedia suggests the candela is in fact an SI base unit with a definition based…

Or not! http://en.wikipedia.org/wiki/File:SI_base_unit.svg
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