One percent accuracy
I can just look at something and guestimate its weight with a 1% chance of accuracy.
I do believe you mean margin of error. Or 99% accuracy.
But enquiring minds want to know, how accurate is it at measuring jubs?
How many boffins does it take to make a LEGO machine to measure a fundamental physical unit? Nine, apparently – but the outcome, a LEGO watt balance, can measure a kilogram with about one per cent inaccuracy. The serious point to the National Institute of Standards and Technology-led effort (NIST) is that with the Le Système …
Is it really necessary to insert an anti american statement into EVERY post you make or are you normally such a dick?
Lego's & Jello are both names that became the common reference for the entire class of product.
This is something any manufacturer would gladly wish for. Mechanno and Playmobil are far less common in the States than Lego.
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Not so, the kilogram is now the only standard defined by a physical object.
For example the metre is the length travelled by light in vacuum during a time interval of 1/299792458 of a second and a second is 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.
So while in a well equipped laboratory boffins can make their own metre and second they have to trog off to Paris to compare their kilo with the actual standard (a lump of platinum iridium alloy). In practice each country has a copy or two of the original or access to someone else's.
Worse still the standard kilo (as located in Paris) appears to be CHANGING (not a lot, but enough).
"Worse still the standard kilo (as located in Paris) appears to be CHANGING (not a lot, but enough)."
I read that they found out that it was accumulating mercury from the air. They had a standard one that was kept sealed, and the day-to-day standard. Every now and then, they would compare them, and found that the day-to-day weight was gaining mass. The last guy who was qualified to polish and clean it, did a final clean before he retired and they analysed what came off. They assumed that the mercury came from the breath of the staff who had amalgum fillings.
For example the metre is the length travelled by light in vacuum during a time interval of 1/299792458 of a second and a second is 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.
If you were quoting those from memory, I'm impressed.
" Plank wavelength of a cat...."
I was always taken with the requirement that to demonstrate any interference in a slit experiment you'd have to have an incoherent cat-beam. Suppose that's easy enough.
Also I guess that a sleeping cat has a zero-point energy that is actually zero
I think it's de Broglie wavelength BTW
Everyone except me. Years ago I prised the Caps Lock key off my keyboard and put it in my desk drawer, where it still resides.
I've often thought that Caps Lock is the most useless key on a standard keyboard, and I would love to design a new keyboard layout which is identical in every way except that it replaces the Caps Lock key with the oft-need-yet-non-existant Any key.
Since the Standard Kilogram has been declared no longer trustworthy, and ISO (or whoever decides) has yet to choose a substitute, I submit that there's no such thing right now as a true exact kilogram anyway.
They never commented on my proposal, which is to simply make 1 kg = the mass of 1000 cc of water, thus defining the kilogram in terms of the meter.