Holy Diet, Batman!

[Frederick L. Simson]

Shrinking Kilogram Bewilders Physicists

[Connie M.]

The "official" kilogram is shrinking, the universe is expanding. What a pickle!

[Laura K.]

The "official" kilogram is shrinking, the universe is expanding. What a pickle!

No wonder they all say we're getting fat. The scales are off!

[Roger H]

I presume, Frederick, that this will put you out of business until someone finds the missing 50 micrograms?

Eureka! I figured it out! There is a fingerprint on each of the other copies making them 50 micrograms heavier!

Roger

[Pete Dumbleton]

I suspect it's a combination of scales being more accurate than when some of the copies were made and the copies may be getting handled more and picking up some weight (Roger may indeed be right about the fingerprints...).

[Roy in TO]

I suspect it's a combination of scales being more accurate than when some of the copies were made and the copies may be getting handled more and picking up some weight (Roger may indeed be right about the fingerprints...).

I'm wondering if it has anything to do with the composition of the original. Platinum and iridium. Wikipedia says:
"There are two natural isotopes of iridium, and many radioisotopes, the most stable radioisotope being Ir-192 with a half-life of 73.83 days. Ir-192 beta decays into platinum-192, while most of the other radioisotopes decay into osmium."
Atomic decay based on a half life of 73.83 days for the most stable radioisotope - occuring over a period of 118 years (almost 584 half lifes) ... just might have something to do with a loss of 50 micrograms.

I can just imagine some scientist breathing in all those subatomic particles every time they open the bell jar.

[Frederick L. Simson]

(Roger may indeed be right about the fingerprints...).

I doubt that particular object has ever come in contact with human skin. Protocol calls for wearing fresh cotton gloves and using tongs to handle class one standards, the highest level of accuracy I get to see. There is a hierarchy of regional and national standards above that, up to that one international standard, with an ever tighter control of handling.

[Frederick L. Simson]

I can just imagine some scientist breathing in all those subatomic particles every time they open the bell jar.

I suspect that the bell jar is only opened within some sort of isolation chamber or glove box, in a similar manner that radioactive materials are handled. The scientist wouldn't be breathing the same air.

[Roger H]

I'm wondering if it has anything to do with the composition of the original. Platinum and iridium. Wikipedia says:
"There are two natural isotopes of iridium, and many radioisotopes, the most stable radioisotope being Ir-192 with a half-life of 73.83 days. Ir-192 beta decays into platinum-192, while most of the other radioisotopes decay into osmium."
Atomic decay based on a half life of 73.83 days for the most stable radioisotope - occuring over a period of 118 years (almost 584 half lifes) ... just might have something to do with a loss of 50 micrograms.

I can just imagine some scientist breathing in all those subatomic particles every time they open the bell jar.

Roy... that's all well and good, but there's a saying in medical diagnostics... "When you hear hoofbeats, look for a horse. The odds of finding a Zebra are small."

You can get as technical as you want about the decay of radioisotopes... my bet is still on fingerprints, or Scotch tape residue, or a coffee with cream and sugar droplet spill... or a left-over wisp of chocolate or caramel from a candy bar...

Roger

[pjanits]

Or the giant coke to go syndrome. Ever so slightly etching away the surface.

[peterh]

Roy... that's all well and good, but there's a saying in medical diagnostics... "When you hear hoofbeats, look for a horse. The odds of finding a Zebra are small."

You can get as technical as you want about the decay of radioisotopes... my bet is still on fingerprints, or Scotch tape residue, or a coffee with cream and sugar droplet spill... or a left-over wisp of chocolate or caramel from a candy bar...

Roger

I can hear echoes of childhood: "Didn't I tell you to keep your grubby fingerprints off my nice, clean kilogram!"

[Roy in TO]

You can get as technical as you want about the decay of radioisotopes... my bet is still on fingerprints, or ...

Yepper, just thought I'd join in on the party

[Pete Dumbleton]

I doubt that particular object has ever come in contact with human skin. Protocol calls for wearing fresh cotton gloves and using tongs to handle class one standards, the highest level of accuracy I get to see. There is a hierarchy of regional and national standards above that, up to that one international standard, with an ever tighter control of handling.

The original may be handled well, but it's all the others I have more doubts about. If enough of them have fingerprints or have absorbed some gasses or something like that, the average of them will rise, making the original seem lighter.


Here's a set of trick questions, and the setting is the US Bureau of Standards, using a triple scale that is perfectly balanced before the weighings.

1. An ounce of gold, an ounce of lead and an ounce of asprin each added to a tray. What will happen?

2. A pound of gold, a pound of lead and a pound of asprin are each added to a tray (emptied from the previous weighings, of course). Will something different happen from the first weighing?


















1. The lead tray will go up and the others will come down.

2. The lead tray will go down and the others will go up.













Gold, platinum and gems are weighed in the Troy System, where an ounce is heavy and a pound is lighter than Avoirdupois, in which the lead and other common substances are weighed. Pharmaceuticals are weighed in Apothecary, which is similar to Troy. If you don't believe this, check they price of gold and you will see it quoted per Troy ounce.