Taking on Airs

Just two weeks of classes to go before final exams. Today I started on the topic of Gases in my general chemistry class. In most popular textbooks today, the relevant chapter shows up somewhere in the middle. Therefore, in our two-semester sequence, Gases occupies an uncomfortable spot. Since our department offers many sections of general chemistry (and labs), the instructors must come to an agreement on the topics to be covered. The last five years, we’ve covered gases at the end of first semester. The five to seven years before we covered it in the second semester. And prior to that it was back in the first semester. We’ve had an uncomfortable relationship with Gases, you might say.

Coincidentally, I have been working my way through Caesar’s Last Breath by Sam Kean. The book is subtitled Decoding the Secrets of the Air around us. The book flap teaser begins with intrigue. “It’s invisible. It’s ever-present. Without it, you would die in minutes. And it has an epic story to tell.” The intriguing book title poses whether you might be breathing in one of the molecules that Julius Caesar exhaled as he died. Of course, the same poser could be made for the first or last breath of anyone in history, but hey, it’s Julius. Thankfully the book spends little time on Julius, because there are many more interesting vignettes the author would like to tell us.

Having previously read Kean’s The Disappearing Spoon and found it not-as-engaging, I did not hold my breath when Caesar’s Last Breath was released. But after recently reading a few more glowing reviews, I decided to check out the book at my local library. The first two chapters were just okay, possibly because I knew many of the factoids and stories, and it felt like Kean was trying a little too hard to be cute and punny with his prose. At that point I almost stopped reading, but I’m glad I persevered. While Chapter 3 (“The Curse and Blessing of Oxygen”) trod familiar ground, the whimsical retelling and intertwining of the tales involving Priestley and Lavoisier started to engage me, even though I already knew many of the factoids.

Section II of the book (“The Human Relationship with Air”), comprising chapters four through six, is where Kean’s writing shines. (I haven’t started Section III yet.) Chapter 4 opens with the mischievous and misanthropic Thomas Beddoes who would “develop a reputation as the queerest man in English science”. A physician-scientist, Beddoes was attempting to use gases as cures. During that time, most folks thought that disease originated from “bad air”, hence the “flocking to seaside resorts and mountain sanatoriums, places where they could breathe free and easy.” Beddoes tested a variety of gases on himself, but I did not know that he was the one who hired another eccentric named Humphry Davy who enjoyed taking “hits” with different gases. Beddoes and Davy went on to promote nitrous oxide to get high. Their Pneumatic Institution was “a respectable clinic” by day, but “resembled an opium den, with [people] lounging around and huffing nitrous gas from green silk bags.” Davy, ever the experimentalist, apparently tested people’s sensory responses while they were high. (I shared this vignette in class today!) Davy went on to become a famed scientist and experimenter, but I had not known about his earlier life working with Beddoes until reading Kean’s book.

Chapter 5 (“Controlled Chaos”) has several interesting tales. I learned about James Watt joining the Lunar Society, Birmingham’s famed intellectual club that “met one evening per month for raucous discussions of literature and philosophy, always gathering on the Monday nearest the full moon. Basing your meetings on the phases of the moon seems charming today, if not downright mystical, but the schedule actually had a prosaic explanation. Members needed moonlight to find their way home afterward.” You could call them Lunatics; there were certainly some strange characters in that group. To help expand the marketing of his steam engines, Watt coined the term horsepower as a standard of comparison, something his customers would easily understand. He “envisioned [the engines] as universal sources of energy – machines capable of powering any mechanical process… Watt dreamed of building the steam equivalent of computers, machines versatile enough to work in any industry.”

The science of thermodynamics grew from Watt’s steam engine, and eventually the horsepower was fittingly replaced by the watt as the unit of comparison. I particularly enjoyed this section because I have been thinking about better ways to connect material from the first semester to the second semester. Students seem to “forget” much of what they learned over winter break. The first topic of second semester general chemistry is thermochemistry, the introductory chapter to thermodynamics. I have often used animated machine simulations to get my students thinking about energy conversion on their first day back. But Kean’s chapter gave me more concrete ideas of how to connect the two pieces, and in fact I should start scaffolding the material now as we go through gases these last couple of weeks.

What got me thinking even more about tying different material together is Chapter 6 (“Into the Blue”). It begins with two sets of brothers, the Montgolfiers and Roberts, competing for the honor of flying the first humans in balloons. Yes, it’s a hot-air story involving many gaseous protagonists. There are many chaotic incidents; which is very fitting as the word ‘gas’ is derived from ‘chaos’. But then the chapter moves to discussing the exploits of Rayleigh and Ramsay. Kean weaves a story of noble gas discovery with spectroscopy, the periodic table, density measurements, and why the sky is blue. Discovering that the noble gases existed as single atoms rather than as two-atom molecules was one of the surprises. Kean ties multiple elements that I would cover in the first semester alone. After reading the chapter I feel sufficiently motivated for yet another makeover of my class next fall semester. I’m looking forward to planning this!