Haven't you often wondered how to measure information? That is, which contains more information the New York Times or the Providence Journal; the Providence Journal or the Brown Daily Hearld; the telephone book or the American Heritage Dictionary; one stand of human DNA vs. one strand of gorilla DNA? How would we define and then make such a measurement? Is there anything in physics and chemistry that might be of use?
When transmitting information like a telephone call, these bits over the internet, a radio broadcast, or military information via sattelite it is important to understand the characteristics of information (and noise, random and not so random). The history of this question goes back to the beginning of the science of thermodymanics to Rudolf Clausius (a picture of Clausius) in 1865 and Sadi Carnot in 1820.[1] It is the subject of the transfer of heat and the fact that "heat does not of itself flow from a colder body to a hotter body."(Click here for streaming RealAudio rather than a download.)
The application of this to the usual concept of information was applied by Shannon working at Bell Telephone Labs and thus was born the modern science of information theory. There is also the offshoot field of operations research or game theory. If we are understanding that entropy is a measure of disorder then its negative must be a measure of order, or information and so the word "negentropy" was coined. Now as originally contemplated by Clausius and the early chemists and physicists, entropy, the flow of heat and all that applied to macroscopic things and did (does not) depend on a microscopic picture of matter. But we do have a microscopic view of matter. There are atoms and molecules and their constituent parts. We also have the telephone transmitting information in the form of bits (digital signals). Eherenfest and Shannon made the connection. Our two experiments illustrate these two differences. In the case of the billiard balls we have "bits" we are keeping track of and in the case of glycerol we have a macroscopic, uniform (except for our ink marker) material.
The Question of Times Arrow and the Passage towards
Equilibrium-Eherenfest's Dog Flea Program.
