Slashdot Mirror

← Back to Stories (view on slashdot.org)

Weighing An Attogram

Posted by timothy on from the more-than-a-soul dept.

Roland Piquepaille writes "Researchers at Cornell University have reached a new level of precision by measuring objects with a mass of less than an attogram (10^-18 gram). They used a silicon cantilever oscillator to measure small dots of gold. But their real goal is to detect and identify viruses. The team also wants to reduce the size of the cantilever, extending the sensitivity well into the zeptogram (10^-21 gram) range. This summary contains more details and an image of a small gold dot resting on the silicon cantilever they used to achieve this breakthrough."

5 of 42 comments (clear)

  1. New tests for gravity. by G4from128k · · Score: 4, Interesting

    If they can use this to measure very small forces on very small objects, they might be able to construct some interesting tests of gravitational fields or of quintessence. We all think gravity changes with 1/r^2 and is irrespective of material composition, but do we really know that this rule works for ALL ranges of mass, distance, and material?

    Inquiring physicists want to know and this innovation could help them know it.

    --
    Two wrongs don't make a right, but three lefts do.
  2. How many... by dnahelix · · Score: 3, Interesting

    How many atoms of gold is that?
    Very fascinating! I love the picture.

    --
    Slashdot Eds Link Anonymous Posts With Logged Posts
    They Are Vermin Feeding On Each Other's Feces.
    I Hate \.
    1. Re:How many... by Beryllium+Sphere(tm) · · Score: 3, Interesting

      Nostalgia department: there was one Asimov novel where a character is walking through a lab, and to convey a sense of wonder Asimov says the lab has a scale capable of weighing a billion atoms.

      I think it was one of the Caves of Steel series.

      Not only can we weigh things, we can identify them at infinitesimal quantities. There was a fact article in Analog about analytical chemistry. There are sensors today that can match the sensitivity of a dog's nose. That field has been advancing at the same explosive rate as computer performance has.

  3. Weight Via Chaos Theory by Doug+Dante · · Score: 3, Interesting

    I had this idea, which I've never implemented, of weighing items with extreme precision using a chaotic system. Since the chaotic system is sensitively dependent upon initial conditions, it should be possible to take measurements over a short period of time and work backwards mathematically to one of several possible initial weights. Eliminate those values that are not possible via other means (negative weights, far too heavy, far too light), and you should end up with an extremely accurate initial weight.

    I'm not sure that it would really work in practice, but I just thought it was a neat idea, and vaguely related to the authors' use of an oscilator.

    Perhaps if they were able to make the position of the oscilator at any time sensitively dependent on initial conditions, they could invent such a measurment tool (e.g. swing another weight in and out based on the position of the oscilator to slightly modify the local gravity in a nonmodal fashion that would make the oscilator sensitively dependent upon its weight and its inital position)

    My differential equations work is so far gone, I couldn't even begin to measure this mathematically anymore.

    --
    The world will not get better through technology. We must seek to be better people.
    1. Re:Weight Via Chaos Theory by Baron_Yam · · Score: 4, Interesting

      Actually, this has already been done... though with optics. You take large numbers of measurements of 'nothing' and note the random static produced by the sensor. You can then subtract the average noise from the average of a large number of measurements of something and get an accuracy level theoretically beyond the ability of your instrument.