The Matchbox That Ate a Forty-Ton Truck by Marcus Chown

I should note up front that I’m kind of jealous of Marcus Chown regarding this book. Subtitled “What Everyday Things Tell Us About the Universe,” The Matchbox That Ate a Forty-Ton Truck is a book that uses trivial everyday observations– the fact that you don’t fall through the floor, the fact that the sky is dark at night– as a jumping-off point for discussions about deep and fundamental scientific ideas like Pauli exclusion and inflationary cosmology. It’s a fantastic idea for a pop-science book, and I wish I’d thought of it first.

The range of topics here is pretty big, covering most of the really weird stuff in modern physics, with a slight bias toward astrophysics and cosmology (which are his home base, scientifically speaking). The explanations move very fast– the first chapter hits the Compton effect, the photoelectic effect, the atomic theory, Maxwell’s equations, the Eisntein-Podolsky-Rosen paper, Young’s double slit, the Schrödinger equation, Noether’s theorem and photon spin in the course of explaining the partial reflection of light off glass, all in just over 30 pages. The hyperkinetic style doesn’t allow for any great depth of explanation, but it serves well to demonstrate the breadth of fascinating science involved in explaining even really simple phenomena.

I do have a problem with the book, though I don’t think it’s entirely Chown’s fault. It turns up in a bunch of places, but probably the clearest demonstration is this bit from the second chapter, explaining why spin statistics are connected to Pauli exclusion:

Think of those two identical particles coming together and interacting at the same spot. Recall that because the particles are indistinguishable, the height of the quantum wave for the event is the sum of the height of the quantum wave for the possibility when the particles are one way round and when they have exchanged places. The two possibilities can be represented by two arrow-like hands on a clock face. And nature permits two situations: the arrows can point in the same direction and add up, or they can point in opposite directions and cancel. The latter leads to the Pauli exclusion principle– zero probability for two aprticles being in the same place or doing the same thing.

So what happens when two electrons, with spin 1/2, exchange positions? Think of two electrons side by side as two identical soccer balls. Since it is important to keep track of their orientations, imagine the two balls are lying side by side in an east-west orientation, with little red flags sticking out to the west. Now make the two balls change places. And do it in the following, rather odd, way. First, roll the western soccer ball round the surface of the eastern one (assume the flag can survive being squashed). This causes its red flag to go from pointing west to north to finally pointing to the east. In other words, the ball moving east goes through a half turn clockwise. Now imagine the two soccer balls back in their original positions and a similar manoeuvre being performed on the eastern ball. Roll it round the western one. this causes the red flag to go from pointing west to south to finally east. In other words, the ball moving west goes through a half turn anticlockwise.

Got all that? If so, you’re doing better than I am. This could be cleared up with a picture, of course, and I’d love to show you one, but the publisher didn’t include one.

This is a common problem, not limited to this book. Science is a highly visual endeavor for most people, and there are tons of great graphical shortcuts to understanding scientific phenomena. It’s almost impossible to conceive of teaching physics without drawing pictures.

And yet, publishers insist on putting out popular science books with no pictures in them. It boggles the mind, especially when that mind is trying to figure out what the hell is up with the rolling soccer balls. Or any of the dozen or so other places where the explanation of some weird phenomenon would benefit immeasurably from an illustration showing what’s going on.

I’ve been reading a lot more pop-science books lately, and doing so has made me much more grateful that Scribner was so good regarding the figures in How to Teach Physics to your Dog— I got minimal comments about the figures included, and those were mostly requests to make the figure clearer, not to get rid of it. Trying to explain physics without any pictures at all is just a terrible idea.

Now, it’s possible that the lack of figures was Chown’s idea from the start, but I doubt it. That whole explanation sounds like the work of somebody who really wants to be drawing little pictures with arrows on them, but isn’t able to.

Anyway, as I said, that’s the biggest problem I have with the book. There are some other minor problems– some of the explanations offered end up being a little too glib (and he has to backtrack at least once), and I think there’s a bit of bait-and-switch in the discussion of the information content of the universe– but on the whole, it’s a fast, engaging read. Nobody is going to read this and then be able to do science, but that’s not really the goal– the whole aim of the book is to get people to say “Gee, the universe is a really cool place!”, and it works very well for that.