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If Public Libraries Didn’t Exist, Could You Start One Today?

An interesting post on the Freakonomics Blog. The hypothesis is that if we didn't have libraries, and someone today proposed establishing locations in cities throughout the country which would buy content once and then lend it out to multiple users at no incremental charge, the publishing industry (and maybe authors) would fight against the idea, or at least set up elaborate payment structures.

If Public Libraries Didn’t Exist, Could You Start One Today?:

Freakonomics update

Since earlier I mentioned how much I was enjoying "Freakonomics", I figure I should give an update now that I've finished it.

As the authors explain, there isn't necessarily a theme to the topics discussed in this book. It's more about applying tools and ideas (data, incenitve, correlation vs. causation) to a variety of interesting questions (why did crime rates drop?, do real estate agents sell their own homes just as they help sell others?, does a baby's name influence the child's success in school?).

All in all, I really enjoyed this book. I listened to the unabridged audiobook version, so a couple lists and tables were read aloud that probably would have looked a little nicer on a page, but it was easy to follow. Now and then I found an assumption to be oversimplified, or less than unshakable. All in all it's great to see data and what should be common sense used explain trends and answer questions contrary to conventional wisdom.

Steven Levitt's name is popping up with more and more frequency, unless I only seem to be seeing it more and more now that I'm aware of it. The book's website has some excerpts and articles and a blog from the authors, if you'd like a taste.

Book Freakommendation

While driving to SF for Macworld, I began listening to an audiobook called Freakonomics, by Steven D. Levitt and Stephen J. Dubner, and I'm really enjoying it.

I suppose I should finish a book before recommending it, but this has already been so enjoyable that I have to give it a plug. It's pretty popular; there's a good chance you seen it or heard of it. If you haven't, this is a book written by an economist and a journalist. It's not a course in micro-economics or anything; it seeks to answer interesting questions ("is there corruption in sumo wrestling?") by considering things like human incentives and distribution of information. There's really no math; any results arrived at by math are explained in a very understandable manner.

It's a bird! It's a plane! It's physics!

This weekend I listened to the podcast of NPR's Talk of the Nation: Science Friday. It included an interview with James Kakalios, a Professor of Physics and Astronomy at the University of Minnesota. Professor Kakalios has a new book coming out called "The Physics of Superheroes".

I can say from experience that he's not the first to use a superhero to try and make the application of introductory physics a little more interesting than most textbook examples. After all, Spiderman is just easier to picture than an "idealized free body". I don't know that I've seen anyone take it as far as it seems Professor Kakalios has.

Here is my favorite line of reasoning from the interview (I'm skipping over the math and ballparking the numbers, so forgive the generalizations).

Superman is able, we're told, to leap tall buildings in a single bound. The original Superman story says that Superman has powers far beyond those of mortal men due to his race coming from Krypton, a planet with greater gravity than earth, and not, as later explained, due to the yellow sun of Earth versus the red sun of Krypton. Early comics specified he could leap 1/8th of a mile into the air. An often-used introductory physics equation asks how fast he needs to leave the surface of the earth in order to leap that high. The answer is something like 140 mph.

An application of Newton's second law (along with a couple of other assumptions) tells us that his legs must be able to apply about 6000 lbs of force on the ground in order to launch him at that speed. Assuming, then, that if his legs are able to supply that force, they are probably genetically coded to support about half of that weight in normal standing weight. In other words, his weight on Krypton was probably around 3000 lbs. Since we know his weight on earth is about 220 lbs, we can determine that the gravitational force on Krypton is about 15 times that of earth.

Knowing the gravitational force of Krypton, it's possible to imagine a model of how the planet of Krypton is constructed. In order to get that much gravity at the surface, you pretty much have to have a planet with a neutron star at its core. And thus (this is my favorite part), it becomes apparent why the planet Krypton exploded. The forces and stresses caused by such a core would make an planet unstable, at best.

Sounds like it might be a fun read.

For more, try the NPR Science Friday audio (download and podcast) and the book on Amazon.