Saturday, September 4, 2010

Magneto-Hydro-Dynamic Flop

Speaking of success and failure, not everything I tried along the lines of experiments and projects always succeeded. Of course, when you’re doing something as a hobby, success has a different meaning than if you’re under the pressure of a contract where there’s a lot of money involved. Still, whenever I started to work on a new idea, I had at least a vague idea in my mind of what it should do, so I could always judge success by whether the experiment lived up to my expectations for it.

Even in the 1960s, people were aware that the supply of oil wouldn’t last forever, and so you would see in the news every so often reports of new technologies for generating power. I have no idea where I first saw the word “magnetohydrodynamic,” but when I did, I fell in love with it. Anything you could apply that word to must be exciting and cool.

Even without reading the articles, I was able to figure out roughly what the word meant, since I knew by personal experience exactly what “hydrodynamic” meant: it was the name of a toy chemical-plant kit I got one Christmas when I was about ten. You built a scale-model framework out of plastic girders shaped like the real thing, and then installed these clear plastic tanks and pipes and valves, filled them with water, dropped in a food-color tablet for entertainment value, and turned on the pump. If you’d piped it right, you were rewarded with the sight of colored water running around in the pipes and valves—at least until the cheap battery-powered motor burned out, whereupon you had to rely on gravity feed for everything, which took the thrill out of it. That happened to me not once but twice—the second time, my mother refused to order another pump unit, since it cost almost as much to buy as the whole kit did in the first place. I am bemused to find that unlike the Lionel Science Kit, the Hydrodynamic Kit was resurrected in 2006 by some Boston engineers who offer it online for about a hundred bucks, which is about five times what Kenner Industries asked for it in the 1950s. But hey—if you have any budding chemical engineers in your family, I can’t think of a better gift.

So if that’s what hydrodynamic meant, magneto-hydro-dynamic must mean water or something flowing and magnetism is involved too. And that’s more or less correct. As I learned from news articles, magnetohydrodynamic power is generated by taking some fast-moving fluid like a rocket exhaust or vapor heated in a nuclear reactor, and running it through a magnetic field. Any conductor moving in a magnetic field will generate electricity, and once that happened, all you had to do is connect to it somehow and get your electricity with no moving parts, unless you count the fluid.

As often happens, it is easier to describe than to do. Magnetohydrodynamic generators are somewhat like their related technology, fusion energy—for both fields, practical use has been about twenty years in the future, for the last half-century. But I knew nothing about the technology’s track record at the time. All I knew was that this would be a great topic for a science-fair project.

I had finally reached the age at which science, if not physics, was actually something you could sign up for at school and take classes in. I must have been in about the seventh or eighth grade at this point. Part of the school science program involved encouraging students to participate in science fairs. The history of science fairs has yet to be written, but as far as I can tell, they were an outgrowth of the big governmental push for improving science education following the revelations in the late 1950s of a “missile gap,” meaning that the Soviet Union was ahead of us technologically, or so we thought. Whether it was true or not, it resulted in an unprecedented outpouring of funding, programs, books, curricula, equipment, toys, and new institutions like the science fair, which was structured like a national sporting event but involved science instead of muscles.

To participate, you had to do a project, get results, and assemble a poster describing your work. I had been doing projects and getting results for years, so I figured adding the poster part wouldn’t be too hard. I had read somewhere about magnetohydrodynamics, and thought I understood the basic principles well enough to build something that would work.
First, I needed a strong magnet. That was no problem: I owned the strongest magnet I’d ever encountered, fresh from a dissection job I had done on a hi-fi woofer. Did I buy the woofer? Not hardly. It was given to me by one of my numerous, well, I guess you’d call them today “donors,” though back then I didn’t think of myself as a non-profit organization and I didn’t keep a list of people who contributed in the past to send begging letters to. But that was what happened, only without the letters. Over the years I’d developed a reputation among family and friends as some kind of techno-nerd, and therefore our house was a great place to drop off unwanted and non-working machinery and electronics of all kinds. I encouraged this behavior, of course, despite the fact that it gradually turned my bedroom, and then a garage apartment we owned, into something resembling a badly run appliance-repair shop’s storeroom.

The woofer, a fifteen-inch speaker out of a monophonic hi-fi set discarded when stereo came out, was the latest victim of my addiction to tearing up any piece of machinery or technology that I could get my hands on, even if it worked. I gradually conquered this addiction late in high school, by which time numerous items which would now be regarded as heirlooms or antiques or both, had succumbed to the bespectacled kid armed with a pair of pliers and a hacksaw. Of course, taking things apart is one way to learn how they’re put together, and in an age where most technology was roughly human-scale (rather than being about the size of a pneumonia virus, as it is today), you could learn a lot by taking things apart.

What I learned from taking apart the woofer was that the black paper cone was attached to a thin aluminum ring that had a few turns of wire wrapped around it. Before I destroyed it, this ring resided in a circular slot at the face of a big chunk of metal that was about the width of my hand and must have weighed six or eight pounds. This was the field magnet. After the cone and the coil had bit the dust, I tackled the field magnet, which was shaped kind of like a thick half-donut or bagel slice, if you can imagine a hollow bagel slice with four cutouts on each of four corners. (I would draw a picture, only it wouldn’t look any good since I’m not an artist.) Anyway, I managed to pry off a field-concentrating piece of steel on top of the thing and got to the magnet itself. Somewhere along the way I dropped it and a small piece broke off, revealing a shiny, glistening complex of crystal facets unlike anything I’d ever seen before. But the magnet was still strong enough to lift ten or fifteen pounds after that mishap, and I was sure it was going to be my best shot at getting something in the magnetohydrodynamic line to work.

The next problem was to get a fluid to flow between the poles of the magnet. I didn’t have access to any rockets or plasma generators, so first I tried water. To get it to follow the curved path through the magnet, I got some plastic tubing that my father used to connect our swamp coolers to the outdoor water faucet with. (Swamp coolers—evaporative air conditioners—are a topic I’ll have to deal with sooner or later.) I cut slots in the tubing and stuck some wires along each side and slathered some epoxy on it in the hopes of making it watertight.

To get the water to flow, I could have used my Hydrodynamic Kit, but the motor had burned out long before. So I just rigged up a big funnel at the top of a piece of wood on a base, attached the funnel to the tubing, and put the bottom end of the tubing into a tray to catch the runoff.
In order to tell whether the thing was producing or not, I got my most sensitive Radio Shack meter, one that measured down to fifty microamps, and hooked it to the wires. Then I put some salt in the water to make it conductive and poured it down the funnel, my eyes eagerly watching the meter needle for movement.

Nothing. Not even a twitch when I managed to get water flowing past the wires pretty evenly for as long as two seconds. I must have fooled with this thing all one Saturday afternoon, and never got a thing out of it.

I was stuck. The science-fair deadline was only a month away, and I had nothing so far. At this point, a friend of the family I’ll call Mr. Hoenig came into the picture.

Mr. Hoenig and his wife had known my parents since before I was born. He had received the closest thing to a scientific college training of any of our friends or acquaintances, having taken a six-week course in meteorology at Caltech after he was drafted into the Army Air Corps during World War II. After the war he started a drug warehouse which subsequently made him a millionaire, but he didn’t act like one. I wasn’t exactly sure what millionaires were supposed to act like, but Mr. Hoenig didn’t act that way. Instead, he was friendly, down-to-earth, and seemed to like me for reasons I couldn’t fathom. My mother once told me Mr. Hoenig had always wanted a son, and his wife had produced only daughters, so maybe that had something to do with it.
Anyway, one day Mr. Hoenig was over at the house or having coffee with my dad, and I told him what I was working on and the problems I was having with it. He asked me, “Would mercury work? I can get you some mercury if you think it’d be worth a try.”

The only dealings I’d had with mercury up to that point was when I’d broken a glass thermometer and played with the shiny globule of metal that fell out of it. How accidental this incident was I’m not sure, but I think our family managed to go through at least one mercury fever thermometer a year, back when that was the only kind there was. When Mr. Hoenig made his offer, I jumped at the chance of getting a serious amount of mercury to play with, and in a few days he showed up with a small brown-glass vial that was very heavy for its size. The label read “Mercury-distilled” and I was back in business—or so I thought.

There was probably about two fluid ounces of mercury in that bottle, about a jigger and a half, so I knew I had to be careful with it. Not because it was dangerous, but because I wasn’t likely to get any more if I lost it somehow. Any idea that mercury was a hazardous substance to fool with was entirely absent from our minds, as far as I can recall. I was certainly ignorant of any danger, and if Mr. Hoenig, manager of a drug company that dealt with all kinds of narcotics and poisons, said it was okay for me to fool with, I wasn’t going to ask troublesome questions. Besides, I’d played with the stuff before and suffered no ill effects, so experience was a strong voice in favor of going ahead.

Mr. Hoenig asked if he could be there when I tried the experiment, so we arranged for him to come over again on a Saturday morning a few days later. That gave me another deadline to work against. I decided to put in a valve to control the flow. We had an old enema bag that was missing pieces and no longer useful for its intended function, so I acquired the rubber hose and the metal clip that squeezed the hose shut. A piece of the hose fit nicely between the bottom of the funnel and the rest of the plastic tubing, which was about three feet long in order to give the fluid some space to fall in and speed up before going through the magnet. The tube felt a little loose, so I wrapped a few turns of wire around it and twisted the ends together to improve the seal. When I tested it with water, the mechanics worked fine—the valve didn’t leak and neither did the joints.

Since Mr. Hoenig had asked to see the first try, I dutifully restrained my desire to try the thing out until Saturday morning and Mr. Hoenig arrived.

The site I’d chosen for the demonstration was the carpeted floor of my bedroom in the front of the house. I had been given to understand that this room had originally been something called a “conservatory” or music room. It was a light, airy place with windows covering most of two walls. Mr. Hoenig, my mother, and my sister gathered around. My father would have been there too, though that particular Saturday I think he had to go up to his office at the bank and work past dues.

All was in readiness: I had connected the meter to the wires, made sure the valve was shut, and I held the open vial of mercury above the funnel. I enunciated a countdown—during the lunar space program, any technical or timed feat of any description was usually accompanied by a countdown. “Three—two—one—hu-u-uh what??!”

As soon as I started pouring the mercury into the funnel, it forced its way past my wired-shut connections like they were tissue paper, and squirted out into the air in a glorious stream that shimmered in the morning sunlight coming through the window. For a second, I was too awe-struck to do anything. Then I came to enough to open the valve and let the remaining mercury run down through the magnet into the catch basin, whereupon it did Precisely Nothing to the meter. But I was hardly paying any attention to the meter. Instead, I faced the challenge of trying to gather up the hundreds of little shiny balls of mercury scattered all over the carpet.
What I hadn’t figured on was how impressively heavy mercury is, and how only a few inches of height gives a huge pressure at the bottom of any container charged with the task of holding it in. Thus the gorgeous fountain of mercury effortlessly fleeing its entrapment to airborne freedom.

Gathering the spilled mercury took some time, and Mr. Hoenig even tried to help. But I abashedly thanked him and said I could do it myself. I think he was a little embarrassed for me, and might have even felt partly responsible for the debacle. But I wasn’t thinking of how he was thinking. All I was thinking was how mortified I was to have concocted this experiment that ended so badly.

It took the better part of an hour, but I picked up all the visible mercury there was and put it back in the vial, much the worse for wear. It now had a tarnished-looking scum on it, and the whole experience turned me off from further experiments with mercury for many years. I kept the vial on my dresser with other mementos and memorials of past exploits, until one year when I was a grad student and the lab I was working at staged a hazardous-waste cleanup day. I brought the thing in and got rid of it that way.

By that time I had realized that, while explicit examples of modern-day metallic mercury poisoning were still hard to come by, it was not a good idea to keep the stuff around in a home setting where it might spill. Still less was it a good idea to keep on living in a room with a mercury-contaminated carpet, as I did for the next couple of years until we moved to the suburbs. The family who bought our house must have ripped out that carpet along with nearly all the other insides of the house, because a few years later we saw the place written up in the Star-Telegram’s remodeled-home feature section. They showed a picture of our kitchen with the original high plaster ceilings carefully restored. “The previous owners,” ran the article, “had installed an ugly false drop ceiling, which we took down as soon as we moved in.” The false ceiling was my dad’s idea. He rigged up the suspended lights in it himself, and prided himself on the fact that a good old boy of his acquaintance had done the job for just a fraction of what it cost the bank to install a similar ceiling in their break room. Of course, our kitchen did look like a bank’s break room there for the last few years, but frankly, it was an improvement over what it had looked like before.

So I’m not too worried that some child grew up sucking on my mercury-laced carpet and lost thirty IQ points as a consequence, though I suppose something like that might have happened. Where mercury is part of the history of a place, it makes sense to take precautions, as I learned once on a tour of Thomas Edison’s West Orange laboratory, now a national historic site. A good many incandescent-lamp experiments were performed there, and the most effective way of evacuating the lamps back in the 1890s was by means of a thing called a Sprengel pump, the operation of which involves tediously raising and lowering guess what?—a vial of mercury attached to a rubber tube. In the nature of things, Edison and his coworkers had encountered some leaks as well, and a good bit of this mercury had found its way into the wooden floors of the lab. The guide told us that we were one of the last tour groups to go through the facility before it closed for a planned multi-year renovation, which included ripping out all the boards with any trace of mercury in them.

And who knows? maybe some half-recollected memory of an old movie on the life of Edison prompted me to build the magnetohydrodynamic rig the way I did, with an elevated funnel of mercury and a long tube. The roots of inspiration lie mostly underground, and it is never easy to tell where our ideas come from. And when they don’t turn out just the way we want them to, it’s just as hard to say why we didn’t think of a reason for the problem, unless we can blame ignorance.

Just the other day, I was conducting an experiment with some equipment I wasn’t that familiar with. I’d made a change in the setup that I didn’t think would cause a problem, but a few hours into the project, the glass door of a vacuum chamber cracked with a loud bang and hiss, humiliating me in front of my student and putting an abrupt end to the experiment. I guess that’s the difference between a novice and an experienced expert: the expert has had time to make more mistakes.

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