Wednesday, June 13, 2018

Caesar's Last Breath by Sam Kean

Source of book: I own this.

Some people line up overnight for the latest smart phone. Other people - like me - get giddy whenever a favorite author releases a new book. I’m a pop-science fan. (Okay, a science fan too.) So, every time Mary Roach, for example, writes something, I am all over it.

One of my favorites is Sam Kean. Sadly, it has been a while since his last book, so I haven’t gotten my fix in three years. Fortunately, my wife got me his new book for Christmas. Here are my reviews of Kean’s other books.

Caesar’s Last Breath is about gases. Encompassed in that topic are history, medicine, as well as the science you would expect. As I have noted, Kean’s style - his strong point - is to write stories. You remember the science because it relates to people. And you remember the people because of the science. In this book, he opens with the assassination of Julius Caesar, then speculates about whether he (and you and me) have inhaled the same molecules that he breathed out. Well, “speculate” is entirely the wrong word. He does that math in detail. (The answer: statistically, you would inhale one molecule on average that Caesar breathed out with each and every breath you take.)

After this introduction, Kean looks at a number of gases found in our atmosphere in light of the past, present, and future, using a combination of stories and science. The first section is about the history of the earth’s atmosphere. That part is pretty fascinating, particularly if - like me - you missed out on too much of mainstream science as a kid. We are on at least our fourth atmosphere here on earth, and the history is really fun. The second part is about humans and the atmosphere. The final part is about the effect we humans have had on the atmosphere. Some parts are depressing, particularly our ongoing contributions to carbon dioxide. But you also get crazy stories, like that of Harry Truman (not the president - a crazy old coot who lived on the flanks of Mt. Saint Helens…) And of the Montgolfier brothers (pioneers of balloon flight), Alfred Nobel, and so many more.

I could go on with fun anecdotes and cool scientific facts, but Kean tells it better anyway.

A few things are worth mentioning, though. First is that we seriously underestimate gases. At sea level, atmospheric pressure is 14.7 pounds per square inch. Not that much - bicycle tires are inflated to a far greater pressure. But that’s a whole ton of weight on every square foot - 20 tons pressing on your body. We don’t even notice, of course, but it is there.

On a related note, it is tough to fathom just how tiny molecules are - and how many of them there are. Sure, we memorize Avogadro's Number in high school. (6.022 x 1023, in case you didn’t remember it…) But exponents are hard to translate to reality. The numbers are too big.

Kean uses an interesting technique. At the beginning of each section, he gives the chemical formula for each molecule he will discuss (say, nitrogen - N2, or nitrous oxide - N2O), then indicates how many molecules you inhale with each breath. This is completely astounding.

Are you familiar with acetylene? (C2H2)  It’s a fuel for flame welding torches. It is a negligible proportion of air: at most 0.0001 parts per million. Undetectable for practical purposes. Medically insignificant. And yet. Each breath contains a billion molecules of acetylene. Say what?! As they say, the poison is in the dose, and the numbers this book contains are pretty good evidence of that.

There are two other references that tickled me. One was to William McGonagall, arguably the worst poet ever. And also referenced in Terry Pratchett’s The Wee Free Men. McGonagall comes into the book because of his poem on the Tay Bridge Disaster, which was related to defects in the iron - hence a discussion of gas metallurgy.  

The final bit that I found fascinating is the explanation of the workings of the “flame refrigerator” - aka the absorption fridge. You may or may not be familiar with these. Most of our modern refrigerators (and air conditioners) use a heat pump to compress and condense a refrigerant (this is also discussed in the book.) However, there is an alternative method, which was developed by Leo Szilard and...Albert Einstein. It uses liquid and gas to accomplish the same thing, but using less toxic materials than those used by heat pumps at the time. (This was before freons were invented.) I think Kean gets one detail wrong about these. He claims that these never made it into homes - but that isn’t quite true. Kean is correct that the heat pump is more efficient and more powerful, and that this is why our homes today use them. But those of us with rural ancestors know that in places where there was no electricity, these - which run off of propane or natural gas - were in common use. I suspect Kean is from the east coast, not from, say, rural Montana.

And, today, they are ubiquitous in recreational vehicles - my trailer has one. That’s why I have refrigeration when boondocking. A little propane flame - heat - makes cold. It’s amazing.

Anyway, this book is quite fascinating, well written, and informative. Let’s hope Kean doesn’t take three years writing his next one.

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