bearing blog

The expert's temptation.

This year in home education, a milestone I've looked forward to:  my eldest son, now in tenth grade, begins General Chemistry.  Also precalculus -- not quite as fun for me to teach as proof-based geometry was, but still, it makes me smile.

For a long time, I didn't expect to teach General Chem at home, even though I'm entirely capable of it.  Because:  labs.  Mark may be quite handy around the house, but I didn't expect him to construct me a fume hood.  And how to dispose of used reagents safely?  And --  all that glassware!  I knew, of course, that one can buy a fully-stocked chemistry kit for homeschoolers; all the catalogues have them.  But I guess I have been a bit snobbish about chemistry:  I never really thought a home-grown chemistry lab could be adequate.  I wanted a proper laboratory experience.

I mean, good enough if you don't have other options, sure.  But we do have other options.  Here in Minnesota, high school juniors and seniors can take courses for credit at a number of local colleges and universities for minimal cost.  (The program's also open to high-scoring sophomores who attend institutional high schools, but not to homeschooled sophomores.  Go figure.)  I have been telling people for years that I intended to have my kids take chemistry in their junior year through the college-credit program, especially so they could take a course in a "real" laboratory.  I figured that we could do physics at home instead.

And then as sophomore year approached, I found myself thinking:  How involved is a first-year high school course anyway?  

I personally racked up a lot of time working with laboratory equipment in high school, it's true.  But now that I think of it, some of that was in the second-year course (yes, I had two years of high school chemistry -- also two years of physics).  And a lot of it was extracurricular activity, such as setting up demos for the summer elementary school chemistry camp, and hours of prep for inter-scholastic science competitions, and sometimes just messing around in the back prep room that joined the two chemistry classrooms.  (Was there really a glass jar half full of mercury on the bottom shelf, glistening dully through a thick layer of dust? Or have I manufactured that memory?  It seems that by 1990 such things should have been long gone.)

Anyway -- what labs do first-year students really do at the lab bench?  Flame tests (not the stupid kind involving methanol, but just putting saltwater-damp probes into Bunsen flames).  Weighing a precipitate to find how close you came to theoretical yield.  Calorimetry -- in practice, this consists of known masses of ice and warm water mixed in a Styrofoam coffee cup with a thermometer thrust through an insulating lid.  I remember the most difficult lab, in the sense of being easy to screw up so that you had to start over and risk being late for English class, being acid-base titration with its impressively towering buret and frustratingly sticky stopcock.  I vaguely remember doing one thing that required a crucible.

Anyway, I spent some time researching, and I found a microchemistry lab kit and manual that began to make me think that we could do an adequate job with the laboratory at home.  Microchemistry:  why didn't I think of that before?   Tiny quantities means less waste, mitigation of safety hazards, and next to no disposal issues.   And after all, there will be a chemistry lab in college.  It's not like this is the last chance the kids have to experience laboratory work.  The fundamental skills of observation, meticulous direction-following, keeping a good notebook, writing detailed laboratory reports are the same everywhere.  

It's the perfect example of how to play to the strengths of this homeschool while mitigating its weaknesses (like no fume hood or convenient hazmat disposal.)

Paper chromatography lab, one of the first in the manual.  With a toddler in the house, the safest place to work is a relatively inaccessible upstairs room with a large table.  A pitcher of tap water and a plastic dish tub serves as a portable sink.  Distilled water comes in plastic jugs at the grocery store.  I purchased a plastic eyewash-station bottle (green-lidded bottle) and sterile eyewash solution from an occupational safety supplier.

 

Microchemistry lab supplies use small quantities, measured dropwise from calibrated dropper bottles and reacted in the tiny wells in plastic reaction plates (there are 96 wells in the plate at my son's elbow).  The reused glass yeast jar contains fruit juice from the kitchen -- one of the liquids subjected to the chromatography lab along with bromophenol blue, copper nitrate, and assorted household dyes.

+ + +

 I'm not just teaching my own son, but two other teenagers.  We meet twice a week for 45 minutes, and if you're thinking, "That's not nearly enough lecturing to teach high school chemistry," you're right.  I wish I had time to teach the teens by lecture 4 times per week.  

If we took two years to get through general chemistry, I could do it; that's exactly how I taught proof-based geometry, which went swimmingly and was a lot of fun too.  The kids studied geometry at half-speed with me for two years, and on the other days of the week they studied algebra at half-speed for two years.  At the end of two years, they had one credit of geometry and one of algebra, just as if they'd done them sequentially.

(It occurs to me now that for future cohorts of children, I might be able to do something similar with science:  Chemistry at half-speed in a full lecture format, while the kids study some other thing at half-speed the other two days of the week:  biology or physics, perhaps.  Two years to do two credits of science.  It could work, perhaps.  H. and I will have to talk about it.  I already have a fully written evolutionary biology curriculum that has no labs, so... it could work.)

As it is, though, instead of following a lecture format, I am following a reading-recitation format.  I am more tutor than lecturer.  With only the barest introduction from me at the end of the previous class meeting, the students read a few sections and work assigned problems (I assign the ones with the answers in the back of the textbook, so they can check their own work).  Then when we meet around my kitchen table, I uncap my dry-erase marker and ask, "Any questions?  Did you have any trouble working any of the problems?"  We work some of the problems together, and then I tell them things like:  The most important thing to remember from this chapter is such-and-such.  Or I tell them a nifty mnemonic (how do I know it's nifty?  My high school chemistry teacher taught it to me, and I haven't forgotten it) to remember which of the gaseous elements are always found as diatomic molecules.  Or I give them a list of ions and molecular formulas that they have to memorize because they are going to come up again and again, and set them quizzes on it until they stick.

+ + +

I'm enjoying something about this that I also enjoyed about plane geometry and am (mostly) enjoying about my son's precalculus work:  Having already set up the schedule so that I know what they are studying each week, I can walk into my class sessions cold.  There are, it turns out, a few consolations for the stay-at-home geek, and one of them is finding out twenty years on that you've still got it,  or at least can fake it in front of newbies.

+ + +

So here's the temptation:  After a few weeks of high school mathematics and science going so well, having put a fair amount of work into designing a course that is rigorous and emphasizes the strengths of the homeschool while mitigating the weaknesses, I sometimes start to think:  Gosh, it's a good thing I've got such an extensive background in this material!  Otherwise how would I ever make sure that my kids learn this?

It's an understandable temptation.  Who doesn't want to justify our past decisions (such as devoting years of our lives to study a field in which we never wind up employed)?  Who doesn't want to feel essential?

But it's one that I am compelled to reject as contrary to my philosophy of education.  Not that it's bad to arrange it so that one's children can learn a subject directly from an adult who's specifically trained in that subject.  This is a great choice!  But -- contrary to what many people imagine -- it is not an essential choice. Being an autodidact has merits too, such as the training in self-discipline, self-examination, and resourcefulness required to find out what one does not know and then to track down the necessary resources to learn it.  Sometimes what's learned on one's own sticks better than what's drilled into one by others.  Probably the optimal mix of an education is one that includes some training by experts along with some mix of self-directed study -- with the exact recipe varying quite a bit from family to family and from student to student.

Even less essential is that the parent specifically be the expert.  Not for nothing am I teaching chemistry and geometry to two other families.  I'm their non-parent expert, brought in in an informal brain-bartering arrangement.  In return, I call on H's skills and (to me) astonishing patience and resourcefulness teaching writing and language arts to all our offspring over the age of four.  Yes, yes, I can write, but can I teach writing?  If I had to, I'd try, but I'll tell you one thing -- I don't enjoy it much at all!

I've also paid money to bring in experts (as in:  music education) and -- admittedly my favorite solution -- I've taught myself subjects so I could turn around and teach them to children.  I'm a quick study, but in principle anyone can do this.  One of the great advantages to this method is that the learning process is fresh in the mind.  Having just learned something presents some surprising advantages to the teacher.

(Something I learned in engineering school:  when a graduate student is not entirely sure that he or she understands a topic, it is a normal occurrence for the student's advisor to assign the student to teach the unsteady topic to undergraduates.)

So, yeah, we subject-experts have to watch how we talk about our expertise to other people, even to other homeschoolers, lest we plant the seeds of the idea that self-teaching is impossible, that experts are always and everywhere necessary.  The answer to "But what qualifies you to teach your own children?" always and everywhere has to be:  I am their parent.  I am motivated to give them whatever they need to see them succeed.   We often look outside ourselves for those resources, but the fundamental resource that powers it all is the resource of self-gift that resides in the very fact that we relate to them as parents are meant to relate to their children:  as mentors in all of life, and education is not really separable from that.

The confidence that learning of some kind is out there to be grasped by anyone with the drive, whatever their immediate limitations, is a fundamental assumption of home education -- and I would say, a fundamental assumption of humanity.  You can do it, if you want, and if your priorities can be so arranged.  It's an optimism that one can never have as long as one is dependent on experts.

The costs and benefits of accountability.

I knew it was coming, because they asked me last year and I told them then that, sorry, it sounded fun but the notice was too short, and anyway I had a new baby. Maybe next year, I said. And then next year turned into this year, and they called again.

Nothing big, a small thing, really: an idea that attracted me, though. A homeschooling co-op had started up in one of the outlying suburbs. They wanted someone to facilitate high school general chemistry, in 90 minute sessions, once a week, on Tuesdays. One of the other parents must have known of my background and suggested my name.

It was a paid position -- I don't know exactly how much it would have been, because it depended on the number of students who signed up: the fees came directly from each student to the tutor ("not 'teacher,'" it was explained to me; I get it, the idea is that the students do most of their learning independently, and then meet once a week for feedback or discussion or something like that.) On the order of a couple of hundred dollars per student for a semester. There was a science lab space available, apparently, which is more than I have at home. I would be free to choose the curriculum, even design my own, as long as it helped the students acquire the equivalent of a high school chemistry credit.

I have a high school student of my own who plans to study chemistry next year, so that was another point in in its favor -- some of the work of curriculum preparation, I would be doing anyway. The money made the offer attractive not so much for its buying power, but that it turned the gig into an actual -- you know -- job, relying on some of my professional knowledge and experience as well as some of the skills I have enjoyed developing behind the scenes, so to speak, over the past ten years.

I had a lot to think about, so I started researching available high school chemistry curricula and lab kits, and also musing about exactly why the offer attracted me.

+ + +

I have zero regrets about walking away from the paid workplace in order to concentrate my efforts on running a family and educating our children. Sometimes, however, I consider a hypothetical future in which I decide I would like to return to it, and I wonder what I might put in motion now in order to help that happen more smoothly.

The missing piece, at least in a tight job market, is really experience that has measurable accountability.

I measure much of my own work against more-or-less objective criteria, of course. Over the years I have grown more and more efficient at setting out a syllabus for the year and more and more disciplined at following it, while also figuring out how to adapt it to make room for interruptions. I have learned what to look for in a textbook, and how to work with what I have available when the only texts are flawed. I have taught myself in a few weeks a years' worth of an unfamiliar technical subject, in enough depth to write a week-by-week guide for a student to work through it on his own. To different extents, I have taught myself three languages. I have spent many hours of trial and error figuring out how to present material to young people who learn in a style vastly different from mine, and to measure the learning of young people who express their acquired skills in ways vastly different from my expectations. I have learned how to give a mathematics lecture on the fly with a quick glance at the book -- let's see, what are we supposed to do today? Oh, that. Well, here we go. I have developed my patience and my flexibility. I know that all this is happening, because every year it gets easier and runs more smoothly, at the same time as it seems I should have more and more tasks to do in less time. This basic sense of growing competence -- at least in the parts where I organize time and environment, write curriculum, and teach willing students -- means that every year I enjoy my work more.

But none of this belongs on a résumé.

Do not bristle about this showing that the work of parents in the home is not valued. The difficulty is that work of parents in the home is not measurable. Home educating develops skills that may be measured; but it doesn't, itself, measure them.

This is inherent to its genius. There is wonderful freedom in home education, which is one of the things that makes the work so satisfying to me. I have no supervisor, and rely on my innate desire to see the children succeed -- plus my desire for order and peace in our home -- plus my own pleasure at digging deeply into a subject -- to motivate me to excel. I know from talking to numerous other home educators that this same freedom can, to others, be intimidating, which is one reason why there is such a big market for school-in-a-box curricula. "I want accountability," they tell me. Whether one wants it or not is a matter of self-confidence and working style; it's absolutely true that, in homeschooling, freedom is free and accountability is something you have to pay for if you want it.

Not being accountable to anyone who is paying us -- trading economic value for economic value -- means that we can't verify these particular skills and strengths for the purpose of selling them. We cannot demonstrate having had to perform to external standards, because the standards we keep are not external. There are no professional references that may be checked to confirm our fitness as an employee. It is a bit like being self-employed, except that even the self-employed can point to the successes and struggles of a small business in a market of other people and the constraints of budgets and regulations, all of which are external and, in principle, verifiable.

This is not something to take personally. It's not about whether parents' work in the home is valuable; it's about whether parents' work in the home is ever capable of demonstrating to a particular potential employer that the candidate in question has something of value in the immediate future to offer to that employer. You have to own the fact that it usually cannot. You have to be satisfied with internal accountability, because there is no other kind. I cringe when I read nonsense like "I'm employed as a Domestic Engineer" or (what is infinitely worse) listing children or spouses as the "employer" on a FB or LinkedIn profile. Even as a joke, this cheapens us all.

+ + +

So I thought seriously about the challenge of having accountability -- with cash on the line -- to other people for a change. I bet I would enjoy it for its own sake, and then, I imagined it could come in handy later; a thing that produces references, and a line on a hypothetical future résumé, a line that combines the professional interests I used to enjoy with the practical skills I have developed doing my, shall we say, undocumented work.

In the end, the attraction to hypothetical future benefits was not enough to overcome the immediate costs. I would have had to drive forty minutes each way; and the subjects that my younger kids could be doing at the same time were not ones I really wanted to outsource; and this particular co-op, it turned out, didn't offer any onsite activities for preschooler siblings. If I weren't already co-schooling two days a week with H, taking one day a week for a co-op day might fill a social void without cutting too much into our schedule. But -- I am, and those co-schooling days are far more valuable to me.

This year things are running more smoothly than ever, and -- when you get right down to it -- adding accountability might strengthen my résumé, but it would weaken my real, day-to-day performance at my primary responsibility. The ultimate end of all work (including work done for personal development and enjoyment) is the support of the family; judged by that standard, this particular work at this particular time would only undermine mine.

Some other year.

Posted with Blogsy

Minglingken.

The first essay at this link is an introduction to general chemistry, written entirely of English words derived from Germanic roots.  There are no Latinate roots, and no Latinate prefixes or suffixes either. 

I have a great love of both chemistry and of language, and the essay delighted me.  In particular, I loved all the creative neologisms created to substitute for words such as "atom," "chemistry," and even "periodic table:"

For most of its being, mankind did not know what things are made of, but could only guess. With the growth of worldken, we began to learn, and today we have a beholding of stuff and work that watching bears out, both in the workstead and in daily life.

The underlying kinds of stuff are the *firststuffs*, which link together in sundry ways to give rise to the rest. Formerly we knew of ninety-two firststuffs, from waterstuff, the lightest and barest, to ymirstuff, the heaviest. Now we have made more, such as aegirstuff and helstuff.

The firststuffs have their being as motes called *unclefts*. These are mightly small; one seedweight of waterstuff holds a tale of them like unto two followed by twenty-two naughts. Most unclefts link together to make what are called *bulkbits*. Thus, the waterstuff bulkbit bestands of two waterstuff unclefts, the sourstuff bulkbit of two sourstuff unclefts, and so on. (Some kinds, such as sunstuff, keep alone; others, such as iron, cling together in ices when in the fast standing; and there are yet more yokeways.) 

  ...Coming back to the uncleft itself, the heavier it is, the more neitherbits as well as firstbits in its kernel. Indeed, soon the tale of neitherbits is the greater. Unclefts with the same tale of firstbits but unlike tales of neitherbits are called *samesteads*.

...Most samesteads of every firststuff are unabiding. Their kernels break up, each at its own speed. This speed is written as the *half-life*, which is how long it takes half of any deal of the samestead thus to shift itself. The doing is known as *lightrotting*. It may happen fast or slowly, and in any of sundry ways, offhanging on the makeup of the kernel. A kernel may spit out two firstbits with two neitherbits, that is, a sunstuff kernel, thus leaping two steads back in the roundaround board and four weights back in heaviness. It may give off a bernstonebit from a neitherbit, which thereby becomes a firstbit and thrusts the uncleft one stead up in the board while keeping the same weight. It may give off a *forwardbit*, which is a mote with the same weight as a bernstonebit but a forward lading, and thereby spring one stead down in the board while keeping the same weight. Often, too, a mote is given off with neither lading nor heaviness, called the *weeneitherbit*. In much lightrotting, a mote of light with most short wavelength comes out as well.

The article was written by Poul Anderson.  Enjoy.   Two other essays (involving English words of Greek origin) follow.

" I'd call for all the chemists who've ever worked with a hexanitro compound to raise their hands, but that might be assuming too much about the limb-to-chemist ratio."

Organic chemist Derek Lowe has another edition of "Things I Won't Work With." 

This post includes a description of how the organic chemist goes about deciphering compound names, which makes it worth a look if you like language.  He also gets in a reference to Verdi opera, incidentally.

I hope he writes a book called "Things I Won't Work With" someday... I would pre-order it NOW.

Low-carb, low-impact.

Mark sent me a .pdf of a very interesting paper the other day:  "Nitrogen and Food Production:  Proteins for Human Diets," V. Smil,  Ambio vol 31 no 2, March 2002. It got me thinking about lower-carb living and sustainability.  

One way to think about farming:  "[A]griculture's principal objective is the production of digestible [nitrogen]."  Nitrogen is a proxy for protein, and its availability in the soil limits how much protein can be produced from the land.  That's why the advent of ammonia fertilizer led to such an explosion in land productivity.  But nitrogen fertilizers have environmental costs, and so we want to use them efficiently. 

-----

Back when I was trying to live low-carb, Atkins-style, one of the things that troubled me about it was that it seemed so... gratuitously meaty.    The Atkins folks are now recommending "at least 4 to 6 ounces of protein foods per meal," "8 ounces... if you're a tall guy," but five or six years ago I had gotten the distinct impression that you were supposed to eat "as much as you want" of bacon and beef and the like.  

Basically, the impression was:  Replace your bread, rice, and pasta with meat, eggs, and cheese.  Right?   And of course, even now, six ounces of protein-based foods per meal is more than a pound a day.   You've got to eat something, right?  And you don't want to be hungry?  And carbs are out?  So high-protein must be in.

But of course this is far more protein than individuals need.  Protein can't be stored,* so eating extra is wasted.   It's greedy, too, on a societal and environmental level; Americans overeat it, and pour nitrogen fertilizers into the soil in order to overproduce it, while in other parts of the world demand outstrips supply.

So why is the Atkins recommendation so high?  I think it's because the Atkins diet sells itself with that "you can eat as much as you want" theory.  The extra meat will fill your plate and your stomach, be satisfying to chew, and taste good; it is made of "normal" stuff that you're used to eating; and if the research on insulin resistance is to be believed, it won't contribute to your fatness.  You can, indeed, lose weight while eating lots of Atkins hamburger salads.

But it's still wasteful, if you're eating more protein than your body needs.  And the more people in affluent nations who try to fix their fatness by following Atkins-style high-meat low-carb, the more overall global demand for meat rises -- and for already-overnourished nations like us, that's shameful.

* * *

This is one reason why, even if we concede that high-refined-carb diets cause obesity and low-carb diets can cure it, we still have a gluttony problem.  A pound and a half of meat every day is a ridiculous amount of meat to eat, even for a "tall guy."  

Let's concede that a small number of obese, insulin-resistant people will not respond to a diet unless it contains virtually no carbohydrates at all.  These few folks will need a diet that's almost all protein and fat, of necessity based mostly on animal products.  They want to eat reasonably-sized meals with enough calories in them that they don't suffer terribly.  Okay, let those few people subsist on mostly meat, and more meat than their protein requirements call for.   Chalk it up as an expensive medical treatment.  But it's terribly wasteful to start there as a first resort for weight loss, or worse, for a lifelong way of eating.

* * *

Here are some things to keep in mind when designing a lower-carb, but more-sustainable way of eating.

1.  Too much protein and too little fat is an important cause of the famous constellation of side effects that accompany "Atkins-style" low-carb eating.

From Gary Taubes, Why We Get Fat, pg 214-216:

This shift [from running on carbohydrates to running on fat] can come with side effects.  These can include weakness, fatigue, nausea, dehydration, diarrhea, constipation, [postural hypotension], and the exacerbation of pre-existing gout.  ... This reaction is why some who try carbohydrate restriction give it up quickly. 

...The reason for the side effects now appears to be clear, and physicians who prescribe carbohydrate restriction say they can be treated and prevented.  These symptoms have nothing to do with the high fat content of the diet.  Rather, they appear to be a consequence of either eating too much protein and too little fat, of attempting strenuous exercise without taking the time to adapt to the diet, or... a web of compensatory responses [from the beneficial drop in insulin levels] that can lead to water retention and what are called electrolyte imbalances.

So too much protein is one cause of the unpleasant side effects.  Eat more fat and less protein -- which means you can eat less animal product and more vegetable oils like coconut, avocado, olive -- and the lower-carb adventure might feel a whole lot better.  (Meanwhile, make sure you get enough salt and don't overdo the exercise).

 2.  Don't overestimate your daily protein requirements.  Three grams for every ten pounds of body weight is slightly more than you probably need -- a number I get from using the recommendation of (0.6 g protein)/(kg body weight)*.  Another way to think about it is one gram per ten pounds of body weight at each of your three meals.  

I weigh 113, so it's doubtful I really  need more than 34 grams of protein per day.  Let's be generous and call it 36:  12 grams of protein at each of breakfast, lunch, and dinner.  So at each meal I can get enough protein from:

• 2 eggs; or
• 0ne-third of a small (5 oz) can of tuna; or
• one smallish chicken thigh; or 
• less than 3 ounces of not-particularly-lean ground beef; or
• almost two ounces of cheddar cheese; or
• a cup and a half of whole milk or yogurt.

Now, if I got most of my protein from plant sources like beans and grains, I might need to eat more, because the body uses the protein in these less efficiently.  And mind you, I don't weigh very much.  If you weigh 250 pounds, you might need twice what I need.  Oh, and growing children and pregnant women will need more than this.  So will someone who does a lot of heavy lifting.  But the point is, if low-carb living means you're going to eat globally-scarce animal protein at most meals, you don't have to consume more than your "fair" share (unless it turns out you have a medical need for it).

3.  Fill the rest of the plate with nutritious vegetables.  Flavor them with enough butter, sauce, oil, or cream to give you plenty of energy.    If you want a low-carb, moderate-protein diet, logically you must eat a good deal of fat.  There is nothing wrong with this.   And the thing that will give it to you, along with a nice lengthy eating experience and a sensation of fullness, is the dressed vegetable side dish.  Eat your veggies, and eat them with plenty of tasty, tasty fat -- not an excess, but enough to give you your daily calories.  This fat need not come from animal products.  The bulk of your calories can thereby come from veggies.

Atkins-style low-carb set an initial upper limit on even salad vegetables, which naturally means the dieters felt they had to eat more meat just to fill up their plates.  Some people might need such drastic limits, but I'm betting that most people will do fine eating as much broccoli, okra, cabbage, spinach, collards, cucumbers, cauliflower, asparagus, and the like as they want.   Might as well give it a try.  

4.  Don't waste so damn much food, especially protein.    Here is a sad statistic:  Somewhere between 25 and 55 percent of the food available to people living in North America, Oceania and Europe is simply wasted.*  Thirty-six hundred calories* are available to every American every day; that doesn't count exports.  We eat too much to begin with, and what we don't eat we waste.  

• A lot of these calories are wasted by retail sellers, who have to throw out expired meat and the like.  
• A huge amount is wasted by the restaurant industry; I don't know this, but I suspect that the fancier they are (i.e. the more operating expense they can pass on to the clientele), the more wasteful.  
• But we also waste a lot of food at the household level, by buying too much and cooking too much in the first place, by over-trimming, and generally by being too picky.   

 I've made this point before:  The first place you can reduce your carbon footprint is by wasting less so you can buy less.   What's more, unlike many other ways to go green, you'll actually spend less money (and maybe even time) on the effort.  (A somewhat frightening implication here is that every time we eat in a nice restaurant, we necessarily contribute to the problem.   Don't really want to go there....)

5.  Choose animal products that make efficient use of protein.  One way to compare protein sources is by feed protein to food protein conversion efficiency.    We could get protein by eating cereals and legumes; or we could feed some of the cereals and legumes to animals, and then eat the animals.  How much of the protein in those cereals and legumes can you get back?  We can accept a less-than-100-percent conversion because animal proteins are more bioavailable to us, and also because they come with valuable fats, nutrients, and iron (not to mention that most of us like to eat animals).  But how good can it get?

According to Smil, the best you can do is dairy products, which give you back 40 percent of the nitrogen (a proxy for protein) you fed to your cow.  Aquacultured fish are next, tied with eggs at 30 percent efficiency.  Eating chickens gives you back about 25 percent of what you "spent" in feed protein.  Pork:  only 13 percent.  And when you get to beef cattle, it's pretty abysmal:  five percent.

It does depend quite a bit on how your beef is raised:

Beef production is inherently the least efficient way of supplying dietary protein through animal feeding. ... This inefficiency is irrelevant in broader [nitrogen] terms as long as the animals are totally grass-fed, or raised primarily on crop and food processing residues (ranging from straw to bran, and from oilseed cakes to grapefruit rinds) that are indigestible or unpalatable by nonruminant species. Such cattle feeding calls for no, or minimal—because some pastures are fertilized—additional inputs of fertilizer-[nitrogen]. Any society that would put a premium on reducing [nitrogen] losses in agroecosystems would thus produce only those 2 kinds of beef. In contrast, beef production has the greatest impact on overall [nitrogen] use when the animals are fed only concentrates, now typically mixtures of cereal grains (mostly corn) and soybeans.

Switching from conventionally raised beef to grass-fed beef is expensive, and not even practically possible depending on the grocery options where you live.    But switching some of your conventional pork and beef consumption even to ordinary eggs and dairy is a cheap change, available to anyone anywhere, that can halve your meal's nitrogen footprint while still providing you high-quality protein, enough to support even a quite low-carb diet.

------

*Asterisked information comes from the Smil paper.

"My grandfather taught [my brother] cylinder safety by throwing cylinder caps at him every time he moved an uncapped bottle or left a cylinder unchained. They hurt."

Derek Lowe writes another "How Not To Do It" post, this one involving acetylene cylinders.  Alarming explosion video included.

(The above quote is from the comments.)

"Behold the s and p orbitals."

From Derek Lowe:  "Generations of students have learned these as abstractions, diagrams on a page. I never thought I'd see them, and I never thought I'd see the day when when it was even possible. As always, I react to these things with interest, excitement, and a tiny bit of terror at seeing something that I assumed would always be hidden."

Counterbalance.

I just finished reading a book that's been out for several years but that I ignored until recently, when I thought I might need a corrective to all the diet books I read last year while I was losing weight:  The Obesity Myth by Paul Campos.  It's been a while since I deliberately read something that I expected to disagree with -- a practice I recommend heartily!

I was surprised to find that the book was in more than one way a wake-up call for me.

The basic thesis of the book is that our public policy towards obesity, and the amount we spend in public and private dollars to combat obesity, doesn't make sense for three reasons. 

Number one:  there's no credible evidence that obesity in and of itself (except at the extremes) causes health problems.   

Number two:  there's no credible evidence that losing weight in and of itself makes obese people healthier.

Number three:  We're not getting much bang for our buck anyway, since the money and effort we've poured into the goal of getting people to lose weight is not resulting in weight loss.  

I will begin with several significant caveats.  I am not entirely convinced by Mr. Campos's review of medical data.  There is not that much of it; I would like to see a much more thorough and detailed cataloguing than is present in this book, one much more like Gary Taubes' analysis in Good Calories, Bad Calories.  I am also certain that some of Campos's data points raise questions that require answers before one can come to a conclusion.  (One example:  he writes that, excluding extreme thinness and fatness, life expectancy increases as you go from lower to higher BMIs.  I thought:  Now wait a minute -- life expectancy also increases as you get older, and people gain weight as they age, so shouldn't there be a correlation there anyway?)  Third, he seems to sort of selectively criticize and praise the practice of controlling for confounding variables.  I agree that this statistical tool can be used judiciously or maliciously, but Campos does not explain why he says it's justified here and not there.  Has he proven that "there's no credible evidence" that obesity causes illness? I don't think so.

However, I think he does succeed in showing something a bit less ambitious:  that the evidence is not nearly as strong as most people assume it is based on media reports and public policy recommendations.   Five arguments he made struck me as very persuasive, if they are true, of this less-ambitious thesis.  I feel I have to add that caveat because I think Campos needs more evidence to demonstrate that they are true.  But if they are true, I agree with him that they call into question the obesity-health connection.

(1)  To demonstrate that obesity causes health problems, most of the studies had to exclude smokers.  (He says this isn't legitimate; I say it is; but regardless, the following point still stands.)  After you exclude smokers and maybe a few other classes of people, the number of deaths in the studies are small.  Nonsmokers in one study had a less than 1-in-600 chance of dying of cardiovascular disease; thinner nonsmokers were less likely to die than fatter nonsmokers, but the number of excess deaths attributable to obesity alone is perhaps not high enough to justify the effort we're putting into combating obesity.  At the very least, the harm of obesity is likely dwarfed by the harm of smoking.  Which do you suppose our country spends more on:  attempting to lose weight and get people to lose weight, or attempting to quit smoking and get people to quit smoking?

(2)  Public policy advisory boards have an astonishing level of conflict of interest.  It goes beyond the level of "this study was funded by that industry which has a stake in the findings."  For example, he says that a claim of a strong international consensus that BMI>25 was based largely on the report of a World Health Organization panel that "consisted entirely of physicians who run weight loss clinics."  Even if you assume a good-faith effort, could such a group really be objective?

(3)  Campos says that studies that purport to show a connection between weight loss and improved health have not adequately controlled for the effect of improved nutrition and increased physical activity; and news reports fail to distinguish this effect too.  Campos gives an example of a study where participants significantly increased their physical activity and as a result both lost a few pounds and improved some measures of their physical health:  the media reported it as "losing a few pounds can improve your health."   It is now very well established that, independent of your weight, physical activity makes people healthier.  (I wrote about this in my post about reasons to exercise.) Because of that, it's obvious that a study purporting to show that obesity causes poor health must control for physical activity.  Campos says that many of the studies don't have that control. 

(4) Taking all the methods together, the act of losing weight introduces significant health risks that have not been adequately compared to the risk of not losing weight.  For instance, he claims that bariatric surgery is shockingly dangerous (the risk of death within a month of the surgery is somewhere between one in 20o and one in 50!).  Is it really proportionally dangerous not to have bariatric surgery, especially at the lower-BMI end of the market?  He says there are health risks associated with traditional methods of weight loss as well.

(5) Being "BMI-normal" or less appears to cause some serious diseases that obesity protects you from.  Osteoporosis, which can lead to deadly hip fractures, is one such disease; there are others.  When you include these "diseases of mild thinness," does the relative danger of mild obesity start not looking so bad?

Since it's true that physical exercise really is well established as something that improves health, it's apparent to me that it's dangerous to suggest "You should exercise to lose weight, because the weight loss makes you healthy."  Physical exercise is not actually that good at bringing about weight loss.  If someone starts exercising to lose weight for their health, they could really be improving their health and yet not see a weight loss; and will they then conclude that it's not doing any good, and so quit?  Or will thin people dismiss exercise because they don't think they need to exercise to be thin?  

 * * *

Not all of the book is about the medical research.  A large part of it is about the social pressure to be thin.  This is the part of the book that, for me, was a wake up call.  Because I've probably been contributing to it a bit over the past year, as I chronicled my own struggles with weight loss.  I hope on the whole my writing has been positive, because I firmly believe that physical activity and well-balanced, not-excessive nutrition are worthy goals in and of themselves, even if they don't result in thinness, and I want my writing to have reflected that.  Still, I measured my success last year largely in the pounds that came off the scale, and I'm a bit more aware that I emphasized the number too much.

Even in my personal experience, Campos's points ring true.  I've been telling people that I've never felt better since I lost the weight -- but maybe I feel better because I'm so much more physically active, and the weight loss is just a side effect.  

And then there is the lengthy discussion of why we criticize obesity so much.  We say it's about health, but is it really?  Particularly if the medical evidence against it turns out not to be so damning?  Campos makes a strong case that it's about the need for us to have some kind of social pariahs among us, a need to feel superior to others.  (Hoo boy, that hit home.  Consider this post.  And consider that it was after I started to lose weight that I started to write that I was "conquering gluttony."  Look, I'm getting thinner!  It proves I'm becoming a better person!)  

A point I found especially interesting:  Campos, a Mexican-American, argues that the freedom to look down one's nose at fat people has functionally created a way for elite, highly-educated white people to continue to sneer at low-income black and Hispanic people, without having to feel guilty about it:

Precisely because Americans are so repressed about class issues, the disgust the (relatively) poor engender in the (relatively) rich must be projected onto some other distinguishing characteristic... In 2003, any upper-class white American liberal would be horrified to imagine that the sight of, say, a lower-class Mexican-American woman going into a Wal-Mart migt somehow elicit feelings of disgust in his otherwise properly sensitized soul.  But the sight of a fat woman -- make that an "obese"-- better yet a 'morbidly obese' woman going into Wal-Mart ... ah, that is something else again.

He has got a real point (made only clearer by the fact that some upper-class white people would be disgusted merely by the mention of the Wal-Mart, without any reference to obesity at all).

Race intersects with obesity culture in another way I wasn't aware of.  According to Campos, girls and young women in the U. S. who are black or Hispanic are much more likely to have a positive appreciation of their own bodies than are white girls.  They are more likely to evaluate their self-worth independently of their appearance.  They are also likely to have a higher BMI.  And (this is the kicker) at least for African-American women, the denonstrated connection between obesity and poor health is even weaker than it is for white women.   Campos seems to suggest that public health authorities are actively promoting educational campaigns that will sensitize young black and Hispanic women to the dangers of obesity.  If this is true, it is really hard not to come away with the impression that some public health policy amounts to "Let's make black and Hispanic girls feel bad about their weight."   

So here's my final word on the book.  It's not perfect.  It's flawed.  It raises questions that go unanswered.  I'm not convinced of Campos's thesis.  But I think I'm convinced that he raises good points, points that people like me -- who tend toward the weight-obsessed, and who like to tell ourselves that it's "about our health" -- need to read and take to heart.  Some of this seeking after thinness is not necessarily healthy, and it's not necessarily virtuous.

Over the months after I reached my goal weight, it took constant vigilance to keep my weight at 108 instead of, say, 112.  Is it reasonable for me to fear those four pounds?  OK, the truth is I'm really afraid that if I let myself gain 4 pounds, I'll let myself gain 40.  Is that a reasonable fear?  All my clothes still fit at 112.   If I relaxed my diet slightly and became stable at 112, would I be happier or sadder?  And does it make any sense at all to be "proud" of my weight loss?  Even if it's true that gluttony was a big problem before, am I better off if I replace it with vanity and pride?

I think I came away very convinced of one sentence in the book, one of the principles of the "health at every size" movement:  A healthy weight is the weight a person maintains while living a healthy life.  To me, that means while being physically active and eating a well-balanced diet in response to real hunger signals.  Campos derides the traditional approach, but I disagree.  I think traditional "diet and exercise" can help a person create that healthy life; you may have to exercise on purpose in order to get enough physical activity, and you may have to control your eating in order to balance your diet and learn to eat in response to hunger.  I did.  But it does suggest that the number on the scale ought to have less sway on our decisions, personal and public,  and especially on our compassion towards others, than it currently does.

The toxicity of everything.

Conversation at In the Pipeline:  "On the Uselessness of the MSDS."

That's "materials safety data sheets," which are shipped with every substance that can be bought from a chemical supplier, and which famously warn about the horrible toxicity of everything, including sand and distilled water (and, according to a Usenet post linked in the article which is probably an urban myth, vacuum).

It's one of my favorite rants about the problem of over-warning, and it has real consequences that in the end make laboratories safer for lawyers but more dangerous for everyone else; as one commenter points out, when harmless stuff and deadly stuff can both be labeled "Toxic," who pays attention?  And where do you go to get real information about how to protect yourself appropriately from exposure?

One very interesting possibility in which information dissemination appears to be coming full circle:  As the official, government-approved channels of information become less and less useful in real life practice, will those who need useful information turn back to the age-old channels of folklore, hearsay, anecdote, oral legend?  It's "unofficial" but its anonymity (and consequent immunity from lawsuit) shields it from danger-warning-creep.  In the modern age, is this the niche occupied by wikis?  Already underway:  a new chemistry wiki, including a category for personal protective equipment.

So, the nature study book for this year is...

 In a previous post I wrote about my philosophy for teaching nature study to elementary-school kids, and promised to mention the book I'm going to use next year with Oscar.  Here it is: Messing Around with Baking Chemistry by Bernie Zubrowski, from the Children's Museum Activity Book series.  (Little, Brown, and Co., 1981; ISBN 0-316-98878-2)

 There are a lot of books about "kitchen chemistry" out there, and most of them don't really fit my style.  This one, however, is a little bit different.

The usual problem with many of these books of demonstrations -- I do not call them "experiments" -- is that they are all about being impressive, and only superficially treat the deeper reasons why the material works.  A particular handicap is that the level of chemistry knowledge which elementary-school-age children might actually be able to assimilate -- inorganic solution chemistry -- is not readily available in the home kitchen, and most of the solutions that change colors or do otherwise interesting things are, um, toxic.  So the kitchen chemistry books play with baking soda and vinegar and call the one a base and the other an acid, and demonstrate that acids and bases combine to give off carbon dioxide.  Also that this is how volcanoes work.  Um.  No.  

For good reason, introductory chemistry courses in formal study -- high school and college -- do not begin with sodium bicarbonate, but instead begin with inorganic hydroxides.   Nor do they begin with acetic acid, but instead with inorganic acids.  They are simpler systems that readily demonstrate basic principles of stoichiometry. (You try to demonstrate Dalton's law of Multiple Proportions in your kitchen when your reaction evolves a gas.)  

Because this tendency in kids' science books irritates me so much, I never thought I'd use one that relies heavily on baking soda and vinegar.  Well, I spoke too soon.   This one's pretty good.  

For one thing, it doesn't pretend to teach the fundamentals of chemistry.  Instead, what it's teaching are the fundamentals of laboratory practice:  as I wrote in my earlier post, "developing skills of safely handling, carefully observing, accurately describing, faithfully reporting, and logically analyzing."   And I think with a little bit of emphasis on my part it can also teach that "we can learn from our experiences and make predictions about the future, and when our predictions are wrong we have still learned something" -- this is no less than the fundamental postulate underlying all of natural science.

For another thing, it is honest about its limitations.  Zubrowski writes in the introduction, "What this book is about is how to investigate the chemistry of cake and bread making."  Indeed, "how to investigate" -- not "This book will teach you all about the chemistry of cakes" or "this book will teach you why cakes and bread rise" or "this book will teach fundamental concepts of chemistry."  

No, what it does it encourage kids to begin with recipes, change them, and observe the differences in the results.  This is different from most of the activities in kids' kitchen chemistry books -- it's not just a demonstration ("Drop some food coloring in a jar of warm water and a jar of cold water and see what happens!  If you did it right, you'll see that the color spread faster in the warm water!"), it's actually an experiment.   If I require the child to keep a laboratory notebook and run parallel experiments with "control" cakes, then he'll really be doing a real experiment -- much like my soaked-flour-in-the-bread-machine series I wrote about earlier.

The experiments in cake-baking are followed by activities that demonstrate the effects of mixing various liquids with baking powder, and the author does not commit the error of calling these  activities "experiments."  He writes, "If you play with baking powder by itself you will find that it does some very curious things..."  and suggests that the child keep a record of his observations.  To introduce an activity in which the baking powder is mixed with soap water, he writes:  "Now here is something special to try that will show you what happens to the baking powder when it is added to the cake batter."  The explanation:  "The foam, especially in the sudsy water, is similar to what happens in cake batter. The water in the milk in the batter reacts with the baking powder to make small bubbles.  In the sudsy water, air is trapped by detergent film.  In the cake the combination of flour, eggs, and milk forms a sticky dough that traps the bubbles as they are formed."  

This is accurate, unpretentious, and uncondescending writing for children about science (and about cooking).  Compare this to the language in, say, The Everything Kids' Science Experiments Book by Tom Robinson:

Question:  What makes things fizzy? 

 In this experiment, you will produce different combinations of mixtures that react to form fizzy solutions.  You'll start with a baking soda/vinegar mixture and then move on to produce your own safe-to-drink, though not particularly tasty, lemon soda.

Science concept:  Certain materials, when brought into contact with other materials, react in a way that forms bubbles.  Acids and bases often combine to form carbon dioxide, which, as a gas, is what makes carbonated soda fizzy.  You'll be experimenting with several common ingredients to determine which react in this way.

The last statement is an out-and-out lie, and the thing about acids and bases "often" combining to form carbon dioxide is... well... misleading at best.  Not to mention implying that this is how soda drinks are carbonated.  Oh, by the way, one of the "reactions" is dropping a lump of dry ice into some water, which illustrates a physical (not chemical) change.  

Back to Zubrowski.  Because he has kids making small cakes (6 Tbsp of flour in each one), we can use that to discuss the concept of scale-up.  Because he has kids comparing recipes that have been altered by one change at a time, we can discuss experimental design and controls.  There are several activities where mixtures of different quantities are compared, so the importance of measurement and careful replication is demonstrated.  Different brands of baking powder are compared:  since these will, of course, have different prices, there's a nod to economics and to variations in quality control from different suppliers, which Dad-the-process-engineer is really going to appreciate.   A suggestion that the child try making a baking soda cake with orange juice leads me to think the child ought to be able to design his own recipe based on what he's learned from the previous experiments.

  Gas collection systems begin with crude balloons-on-bottles but progress to the child's building a gas generator and a collection system in which the volume of gas can actually be measured.  (Here's where I'm going to go the extra mile and get some lab equipment -- no need to bore holes in rubber balls stuck in the necks of jars when I have access to online retailers that will sell me value-priced two-hole stoppers and Erlenmeyer flasks).  The child is encouraged to try several activities that demonstrate the properties of the gas.  "Experiments?"  No!  Zubrowski writes, "Just what is this gas?  Is it plain old air or does it have special properties?... One of the jobs of a chemist is to find out about things like this.  Scientists have developed all sorts of tests for substances to find out exactly what they are.  Here are some you can try." He goes on to tell how the child can demonstrate that the gas doesn't support combustion, is heavier than air -- a chance to explain molecular mass! -- and dissolves in water to form an acidic solution).  And then, rather than claiming that all these tests prove it's carbon dioxide, he warns the reader "You would need to do other tests to establish this fully..."  (Guess what.  I can buy saturated lime water online.  Problem solved.)

Why does the language matter so much to me?  It reminds me a little bit about my philosophy towards child discipline. With discipline responses, the most important thing to me isn't whether a given technique, or way of explaining things, "works" (appears to give immediate results).  I obviously don't want to choose things that turn out NOT to work, but not just anything that appears to "work" will do.  Ultimately, I choose techniques and language that I am comfortable using:  language and actions that communicate the truth, namely,  that the child is a human person deserving of respect while learning, AND that I as his parent have a real, natural, and just authority over him, AND that I expect him to learn to comport himself more and more as he gains experience and maturity.  If I can't find something that meets both those criteria (truth and effectiveness), I'm going to do my best to try to come up with one, and in the meantime I err on the side of truth over apparent effectiveness.  Because I believe that the truth IS effective, even if it seems to take longer than, say, duct-taping a kid's mouth shut.

For the same reason, I need to use books that use language I can stand to hear.  Language that isn't dumbed down so much that it no longer accurately describes what's physically going on.

So... even though Exploding Color Changing Slime may appear to get kids interested in science, really it only demonstrates that kids are interested in exploding color changing slime.  Which is not representative of "science."  I'd rather introduce children to what workaday science really means:   observation, measurement, recording, communicating, repeating and repeating and repeating, calculating, predicting, testing.  It is not, perhaps, as impressive; it perhaps will not produce wide-eyed wonder, at least not right away.  But it is true, and I think there is a special kind of quiet fascination that some children can find in the thought:  I can do this.  I can discover this.  I can measure this.  I can find it out for myself.  It takes longer to develop, but I think it will stick.