Oct. 23, 1997
Vol. 17, No. 3

current issue
archive / search

    Learning physics with 'Schroedinger's Dog'

    By Diana Steele
    News Office

    STACEE physicist Corbin Covault has one collaborator who will never see his name on a scientific paper or receive tenure at a research university, but who nevertheless enjoys a degree of fame and is an accomplished physics instructor: he is Munro, a golden retriever owned by Covault (or maybe it's the other way around?). Munro has his own Web page, "The Munro Channel," and often demonstrates fundamental mechanics to undergraduates in the physical sciences core courses.

    "Munro is very good at demonstrating things like projectile motion," said Covault. "I use a cannon that shoots tennis balls across the room, and I ask the students to calculate, based on the velocity of the ball and its trajectory, where Munro should be placed in the room in order to catch the ball in his mouth. Sometimes this works better than others -- not because the students' calculations are off, but one year Munro was enamored of someone in the front row, and the ball bounced off his forehead. Clearly, he was in the right place, but he wasn't focused on the experiment.

    "Other times I've used a Frisbee with Munro to demonstrate rotational motion. But really my favorite demonstration is something I call 'Schroedinger's Dog.' There's a famous paradox in physics called Schroedinger's Cat, which I've adapted to be animal-friendly rather than animal-hostile."

    Schroedinger's Cat encapsulates a quantum-mechanical paradox. A cat is placed in a box, together with a radioactive atom. If the atom decays, and a Geiger counter detects an alpha particle, a hammer hits a flask of prussic acid, releasing toxic fumes that kill the cat. The paradox is that the cat's fate is tied to the wave function of the atom, which is a superposition of both decayed and undecayed states. Schroedinger said the cat must therefore be both dead and alive -- a superposition of both states -- until an "observer" opens the box and "collapses" the wave function.

    In Covault's variation, Munro is the "cat" -- in a cage under a tarp -- and a cookie replaces the prussic acid. The superposition of states is "hungry dog" and "happy dog." Covault said, "The point of this exercise is to demonstrate how absurd and weird the results of quantum mechanics seem to be. How do you interpret quantum mechanics? What is the role of the 'observer?' How can something as complicated as a dog or a cat actually be in two totally different states at once? And doesn't Munro count as an 'observer?'

    "By the way, when we actually ran the experiment, the result was a hungry dog. I gave Munro the cookie anyway."

    You can visit Munro at "The Munro Channel," http://hep.uchicago.edu/~covault/the_munro_channel.html. This site shows pictures, updated every five minutes, of what Munro is doing now (usually sleeping), and has an archive of "cute" photos and "facts about Munro." His next classroom appearance may be during spring quarter, when Covault teaches PhySci 112.