The World's Roundest Objects: Perfect Silicon Spheres.

Posted by Alex in Pictures, Science & Tech on June 17, 2007 at 12:09 pm


Australian scientists are trying to create the world’s roundest objects: perfect silicon spheres to define a kilogram:

Scientists will use the spheres to determine how many silicon atoms make up a kilogram, and this will be used as the new definition — bringing the kilogram into line with other base units such as the metre and the second, which are all defined by physical constants.

"It’s really an atom-counting exercise … and we’ll come up with a new definition of the kilogram based on atoms, rather than based on the thing in Paris," explained Walter Giardini, of Australia’s National Measurement Institute.

Link

That thing in Paris is a solid platinum-iridium cylinder kept at the Bureau International des Poids et Mesures (BIPM), which mass is, by definition, exactly 1 kilogram.


International Prototype (Image Credit: BIPM)


Previous post
this post? Please Email this               
Next post


FUN PRODUCTS FROM THE NEATORAMA SHOP:
BuckyBalls (w/ Mystery Bonus!)


COMMENT

7 comments to "The World's Roundest Objects: Perfect Silicon Spheres."

  1. Chris
    June 17th, 2007 at 2:13 pm

    not at all interesting for any good American.
    oz. & lbs. rule!

  2. Gitai
    June 17th, 2007 at 7:15 pm

    Wait a minute. I thought that the kilogram was defined as a thousand grams, which equals the weight of one cubic centimeter of water.

  3. jonno
    June 17th, 2007 at 10:02 pm

    the water based cubic centimeter isn't perfect. it depends on pressure.
    counting an exact number of atoms is better.

  4. aj
    June 17th, 2007 at 10:08 pm

    @ Gitai, I think thats an approximation, it's not considered good enough for high accuracy experiments where they work in sub micro-gram ranges.

  5. vandoo
    June 18th, 2007 at 10:16 am

    figures some American would be the first to rip this.
    I am pretty sure your military uses the metric system and they are as "good American" as you can get!

  6. mmmark
    June 18th, 2007 at 11:14 am

    Vandoo- Yes, Chris is either a fool, or he's simply joking, or he's trying to goad folks into posting the typical anti-USA comments. Most Americans use both metric and US standard measurements, and all scientists use metrics daily. There is no "contest" between them here in America.

  7. Sid Morrison
    June 18th, 2007 at 11:50 am

    "mmmark" has gggood cccomments. American engineers have no troubles (except for NASA and its subcontractors maybe) working in all kinds of mixed units. I'm used to seeing pressures expressed in psi, Pascals, bar, inches of mercury, inches of water, atmosphere, etc. You deal with them all and it's no biggee.

    As for the kilogram standard... I am in favor of anything that removes this from the custody of the French. There is no telling when they might get invaded again and lose control of the kg prototype, Think what could happen if that were to fall into the hands of the wrong people! Now who is going to invade Australia? The New Zealanders? not likely...


PLEASE LEAVE A COMMENT

Neatorama Comment Policy
You don't have to register or login to comment, but it's easier if you do so. Comments aren't censored, but those that are abusive or off-topic may be edited or deleted.


Stay updated on the comments with Comment RSS