links for 2009-04-20

  • Sure, it looks like a really good book about physics. But where’s the talking dog?
  • "In the physical sciences and physics especially, science follows an infinite loop procedure. I’ll label them 1 and 2, though it’s really a chicken-and-egg thing. This is the way physics works, simplified:

    1. The experimental results produce data which suggest ways old theories could be refined, replaced, or strengthened.
    2. The new theoretical descriptions and predictions suggest new experiments to test the accuracy of those theories. Go back to step 1.

    And recursively the theories become better and better approximations to reality. Some theories like QED and general relativity are literally perfect as far as we can tell, though most physicists expect that (say) general relativity will eventually require changes at very high energy."

  • "I remember when I was discussing a story about fast-charging batteries with someone that there was the conjecture that this was the hurdle to getting electric cars on the road. And I realized it wasn’t — heat dissipation issues aside (charging a cell-phone battery is one thing, but trying to scale that up is quite another) — the real issue is how much energy you need and how quickly you can deliver it. Grid capacity."
  • "The experimental claim, coarsely described, is that after some time, cells containing heavy water under these conditions begin to get hot (but not cells containing ordinary water!). Ideally one does good calorimetry and can measure the amount of energy that comes out of the cell in the form of heat, vs. the amount of energy put in in the form of integrated electrochemical current times voltage. The claim is that in some such experiments, the inferred amount of energy out is much larger than the electrical energy in. This is "excess heat".

    So, what’s the problem? Well, there are several issues."

  • "Think of it as a challenge…"
    (tags: math comics silly)
  • "[T]he KSM example seems to put the practical question to rest altogether. If waterboarding was an effective torture technique, why on earth did officials feel the need to administer it 183 times on one individual? What kind of sadist thinks, "We didn’t get the information we wanted after torturing him 182 times, but maybe once more will do the trick"?"