The cost of the learning curve.: hoses and fittings that ended up NOT being helpful in reaching my target vacuum.
My idea of creating a vacuum was terribly simplistic. Just run a pump until you reach your desired vacuum, right?. Well… I learned that there is much more to it.
First, there are different degrees of vacuum, categorized by how difficult it is to attain them. The easiest can be obtained by a mechanical pump, a piston, or equivalent, pushing air molecules from the chamber to the outside, essentially a reverse bicycle pump. It is possible to remove 99.9% of the air molecules and a few more, but that still leaves too many for the cool vacuum electron effects like neon signs, nixie tubes, and for audiophiles, amplifier tubes.
The mechanical vacuum pumps can’t reach those levels; more exotic pumps are needed, but they can get close to where radiometers operate, which is my interest. So following the advice of expert friends, I acquired a pump that, in principle, could reach the level of vacuum I needed: 50 microns (a micron of mercury air pressure is 1/760 thousandth, call it a millionth, of standard atmosphere). The pump model I bought is commonly used by the HVAC industry, where air conditioning units need to be evacuated before charging them with refrigeration working fluids (Freon, etc.). They can reach the 50 micron vacuum level internally, but if you connect it to a real world vacuum chamber, there is a myriad of “leaks” that will prevent getting there.
I found this out by trial and error. I found that the hoses, fittings, and gauges from the HVAC world were not cheap, but there is a market to keep them reasonably affordable to the industry’s practitioners. Vacuum-rated hoses, gauges, valves, and fittings (the connectors between vacuum elements that minimize leaks), are hard to make. And they all seem to have their own connection systems. I learned about “flare” fittings, “nominal pipe thread” and tapered thread, acme threads, o-rings, and a bunch of other methods for connecting things and trying not to leak air molecules.
I decided that to become more skilled, I would need my own torch and materials so I could practice and make as many mistakes as needed to acquire a specific glass-blowing skill. I found a torch on eBay, some hoses and fittings on Amazon, a tank of propane from my barbeque grill, but then had to figure out an oxygen source. I also needed an exhaust system so I wouldn’t asphyxiate while heating glass from my propane-burning torch.
The exhaust system was simple in principle, but of course, the actual implementation was not. I wanted to create a “glass working station” in a corner of my garage/workshop—a recently built structure with a 10-foot high ceiling with no explicit ventilation. This has already been a limitation when I wanted to work with paints, adhesives, or solvents that required a ventilated area, so I welcomed the excuse to create a ventilation zone for my shop.
Professional paint and chemistry booths are expensive, so I looked for kitchen exhaust hoods. I discovered that they have an enormous price range which depends almost entirely on the current popular style and appearance of the sheet metal hood, and almost nothing on the exhaust rate of the fan. The typical kitchen exhaust rate was less than I wanted anyway, so the fan didn’t matter—I would be replacing it. I really wished I could buy the exhaust hood sans fan motor, but they are rare. And when you find them, they cost the same or more. It’s the external visual style you are paying for.
I found a low-cost, unattractive but functional, kitchen exhaust hood with a low-power motor that I could replace with one that was more capable. It seems a huge waste, but these are the tradeoffs in the DIY world.
I was recently struck by an unexplained desire to craft a classic scientific object, a “radiometer”. It was first created and demonstrated in the 1800s as scientists explored the fundamental elements of nature, especially the behaviors of atoms and molecules. The periodic table and the ideal gas law that we learned in school were figured out during this time through many careful experiments.
Among the experiments was one performed by William Crookes while trying to isolate and identify his newly discovered element Thallium. To make high-precision measurements of mass, he avoided the disturbances of air currents on his balance by putting it in a vacuum. But he found that the readings were still varying, depending on whether the balance was in sunlight or not. With his laboratory skills, he crafted a device to demonstrate the effect, a device that today is known as a “Crookes radiometer”, or “light mill”. It is a delicately balanced arrangement of vanes, black on one side, white or silver on the other side, suspended in a glass vacuum tube. Crookes discovered that when the vanes were illuminated by sunlight, they moved, rotating around the balance point, demonstrating that light induced some force to cause the rotation, and that force was also responsible for the variations in his mass measurements. See this account for a wonderful history of the radiometer. There is still some scientific uncertainty about how exactly it works!
My fascination with the Crookes radiometer began as a child when I first saw one spinning in a store window. My dad was with me and was able to explain it to the satisfaction of his 8-year-old son: “The light hits the white side and bounces off, but it gets absorbed by the black side and the difference of force makes it move”.
I immediately set out to make one for myself. With black and white construction paper I made some vanes and taped them to a pencil. I found a sunny spot in our backyard and planted the sharp end of the pencil into the ground. Nothing. No motion. It was quite a disappointment.
When I later explained to Dad that my radiometer didn’t work, he told me that the force of light is very small, and for it to spin required a very delicate balance and removing the air from around the vanes, which was why the radiometer at the store was inside a glass bulb. It explained why my backyard radiometer had failed, but it didn’t quench my curiosity.
The QSL postcard sent through the postal service is the mechanism used by ham radio operators to confirm their over-the-air radio contacts. This is my dad’s QSL card for his Idaho station.
As an electrical engineer I learned that “all digital devices comprise analog components”. This has remained true even as quantum effects are now being utilized in computational logic gates (they are defined by analog wave functions).
Radio waves, especially those used by amateur radio operators, are analog signals transmitted and received by oddly shaped and configured pieces of conducting metal parts known as “antennas”. And the techniques to couple a useful signal to them are part of the arcane art and science of amateur radio. The sharing of this knowledge is a big part of the ham radio community ethos.
So I should not have been surprised to receive an email asking for help with “s-meter calibration” of an antenna. It was addressed to my dad, who died in 2016, but whose email address has been set to forward everything to me. I get occasional messages from this account, but with diminishing frequency, and usually from some company or service he had subscribed to, but for which there was no “unsubscribe”. In this case however, it was from one of his fellow ham radio acquaintances looking for advice.
Who are these people, and why are they jumping out of hyperspace?
This is a computed image. It started as a snapshot of a group at a lunchroom table. There was nothing particularly significant about it except as a record of a pleasant reunion of this group of old friends. And like many such shots of a group at a long table, it is hard to get them all in the frame and to represent each member in a photogenic pose. In particular, the persons at the far end of the table are lost in the distance. It is particularly noticeable with wide-angle lenses, the default for phone cameras.
My test image, a scene shot using a wide angle lens of a group at a table. Photo courtesy Fred Nourbakhsh.
I wondered if I could re-image this scene so that the people are more equally sized, the furthest members are not so small, and the closest not so big. This is what would naturally occur if the photographer used a longer focal length lens and stood further back. This is an account of what I learned.
The Roving Photons on the steps of the Physics Building (now the Tate Laboratory of Physics) ca 1975. Standing, left to right: Kevin Loeffler, Richard Dorshow, Thor Olson, Jeffrey Harvey, John Bowers, Kevin Thompson. Squatting: Greg Hull, Curt Weyrauch.
I first attended the University of Minnesota in the fall of 1971. I was accepted to the Institute of Technology, IT (now College of Science and Engineering, CSE) but faced the difficulty of narrowing my interests which ranged from science to art, from mathematics to theater. My initial major, architecture, was inspired by a desire to combine art and science, romanticized by the Ayn Rand novel “The Fountainhead”. That idealistic goal was punctured by the first lecture of Architecture 101, where in retrospect, I recognize that the professor portrayed the profession in its worst possible light in order to weed out students who were not fully and utterly devoted, focused, and dedicated to the field.
It worked. I changed majors the next day.
But I was still registered for all the courses required for training in architecture, including math and physics, important for structural analyses to guarantee the strength and safety of buildings. I continued these courses, and even while shifting my major to Fine Arts, I still wanted to learn “the secrets of the universe”. Eventually, I found the reliability of science to be more aligned with my internal quest than the apparent arbitrariness of the art world. Don’t get me wrong, I admire artists and consider them to be explorers, and the reports from their journeys inspire and motivate me. But I realized that I did not have the qualifications to lead or undertake those journeys.
Instead, I focused on how Nature works; this is the domain of physics. And I found myself in a small group of classmates that were similarly enthused. Somehow (I don’t remember the details), we became members of an informal club, “The Roving Photons,” whose motto was “A roving photon gathers no mass”. We attended the same classes; were confronted with the same contradictory anomalies of quantum physics and we all struggled to make sense of it.
I like to brag about the classmates I studied with. One of them, John Bowers, went on to become a leader in the field of photonics (appreciate your fiber optic internet connection) . Another, Kevin Thompson, contributed to the corrective optics for the Hubble Telescope.
My freshman dormitory colleague Craig Holt, discovered an important physics-mathematical relationship, now named after him, as is an endowment for a scholarship at the University of Minnesota. My roommate during our junior and senior year, Jeff Harvey, went on to become a physics professor and contributor to string theory. Others became teachers and engineers, extending our knowledge of the universe and demonstrating how to utilize it, to the next generations. It all started in our undergraduate classes at the University of Minnesota in the 1970s.
Here is the recollection of one of my classmates and Roving Photon member Richard Dorshow (who later contributed to the development of medical devices and pharmaceuticals), as reported in 2010 by the newsletter of the School of Physics and Astronomy.
“…One of my favorite memories was from my sophomore year. A small group of us formed an undergraduate physics club, The Roving Photons. I was elected Executive Director, mainly because I wrote the rules for election and eliminated the competition. It was a very friendly group of comrades (Greg, two Kevins, Jeff, John and Thor). We were given a small, narrow room in the sub-basement of the Physics building.
“There was an exit sign in the hallway outside the door. Thor, who was also an art major, somehow put the club name on two pieces of glass and we replaced the exit sign with the glass such that we had a lighted club sign. I think the sign lasted less than one night as it apparently violated the fire safety code. We had a refrigerator in the club room and arranged a delivery of pop every so often.
“Our main impact was a faculty lecture we sponsored and arranged. We would take the faculty speaker out to lunch on the day of the presentation. I remember we used to go to Sammy D’s. I think our first speaker was Professor Gasiorowicz. [He was] a favorite, whose explanations of probability usually involved some sort of food analogy: a tablespoon of peanut butter spread over a cracker, many crackers, and then the entire universe to explain probabilities. I still have an autographed copy of his book written and completed during my time at the university.
“The school used to get audited by the American Physics Society and a group of distinguished physicists came to do the audit. This included William Fowler, then president or president-elect of the APS, and also the famous physicist Herman Feshbach. Because there was an undergraduate physics club, the distinguished group talked to us too. Here we were with this group of esteemed physicists and we were telling them about the lunches at Sammy D’s, and the soda pop delivery. In hindsight, this seems a very surreal event.”
Rick’s description captures only a small portion of our experience as students during the 1970s, a turbulent but productive time in physics. A “zoo” of new subatomic particles were being discovered, all of which would be clues leading to the now famous “Standard Model” of quantum mechanics. We were in the middle of it all but didn’t really know. To me, it made little sense.
And it is still challenging. Although I was distracted from my study of physics by the exploding field of electronics brought on by miniaturized transistors (and because just about any physics experiment requires electronic instrumentation), I continued to follow the developments in physics throughout my career. Reading their Wikipedia entries, the inspiration from my superstar classmates of 1975 is part of why I am still curious enough to engage in online courses for learning how to program a quantum computer.
The quantum “measurement problem” has not yet been resolved to my satisfaction, but Schroedinger’s cat is being cornered. The recent measurements of gravitational waves, the unexpected acceleration of the universe, dark matter, dark energy and other fascinating observations may be today’s equivalent of those confusing 1970 particle zoo clues, pointing us to a “New Standard Model”. I hope someday to learn about it!
A sample question at a New Year’s party trivia station
In an earlier life I hosted an annual New Year’s Eve party. It had the usual party elements: holiday decorations, elaborate food, and refreshing beverages. It also featured a trivia game, something that started as a simple mixer to help our eclectic set of friends from the different avenues of our life to meet and engage, with the intent of adding to the good will and good cheer of the evening.
We created a series of “stations” throughout the house, each with a set of questions. Our guests were organized in teams of two and they would do their best to answer them. The questions were selected and designed to fall in the category of “common knowledge” and “things everyone should know”. It was surprising how many we don’t, and the newly formed duos would try their best to compete for the “fabulous prizes” (usually a trophy coffee mug) presented to the team that got the most right.
The annual trivia game was often described as a frustrating or humbling experience, but as embarrassing as it might have been to our guests when they could not answer our simple questions, they kept coming back each year. Perhaps they thought that next year they would be partnered with someone who would actually know the figures featured on each bill of US currency, or the numbering convention behind the interstate highway system, or the counties that make up the metropolitan mosquito control district. I eventually learned that everyone wanted to partner with my friend Rich, who may not be up on the latest trends, but seemed to know the other questions on topics we all learned in grade school but somehow forgot.
I was a teenager when asked to help stage this photo for my grandparent’s 1967 Christmas card.
I recently ran across some speaker notes that I used almost 30 years ago on the occasion of my grandfather’s 90th birthday (1994). I recall that a large white party tent had been set up on a backyard lawn and was filled with four generations of my grandparents’ descendants and their remaining lifelong friends. Here are my comments for that day.
I’ve been blessed by not only knowing, but sharing in my grandparents’ lives for many years (I am over 40!) Many of my friends and colleagues do not even remember their grandparents.
They told me I would be speaking at this gathering, but did not tell me what to talk about, so I just picked something that appealed to me. I’m going to tell you a little about an activity that my grandfather undertakes each and every year and we are all the beneficiaries of—their annual Christmas greeting card.
He’s been making photographic Christmas cards for over… well, I don’t know how many years. I was planning to make copies of some of the great ones over the years as a slide show, but then I found out that this party would be in the afternoon, outside!
So instead, I made some posters, and if my assistants will help hold them up I will describe them…
As I mentioned in an earlier blog entry, I inherited a collection of 16mm movies made by my two grandfathers, each an enthusiastic amateur and early adopter of photo technology. I have been struggling with their fate, as they consume a not-inconsiderable amount of space in my archives. Space that could be used to store other useless artifacts.
They have now been (mostly) digitized. And one can find them summarized at this page.
I have great difficulty getting rid of things. As someone who respects the historical path that brought us to our current time, place, and relations, it is hard to discard mementos, especially (for me) photographs that captured moments along that path. As a scientist, I am loathe to delete “data”, that might someday be valuable.
I have to acknowledge the slim likelihood of such artifacts becoming valuable. I hold no conceit that some biographer will ever be looking for scraps and clues identifying the influences on my own childhood. I like to think that my contributions to society have been positive, but probably not worth much more than an oblique reference in an obituary (“he was a curious man”). But maybe there were things in those movies that would be of interest to someone else. I didn’t know how to find that audience.
So the movies, spooled on metal reels of various sizes, lay dormant for years. When I wondered about their ultimate fate, I realized that eventually, they would have NO meaning to anyone, even if it were possible to view them. If there was any value to be extracted, it would have to be now, by me.
I described that initial effort in the previous post on this topic. Here is what has happened since.
Grace and Hoan, with mom Poldi, after presenting me with this terrific gift.
I recently received a most unexpected gift, an extravagant thank-you gesture from newlyweds for being part of their marriage (as driver and other small supporting roles). Somehow, they found something that would appeal to me on many levels, something I would never consider for myself: a LEGO set! And not just any LEGO set, a large and elaborate architectural depiction of an A-frame cabin, with thousands of parts.
It had been inspired by a LEGO enthusiast from Italy, who enjoyed creating Lego models of houses in his spare time. Evidently, there is a large community of LEGO fans, large enough that there is a program for them to submit ideas and models for the pleasure and approval of other fans. Those with the highest votes are selected to become an actual LEGO product. How brilliant! Let fans come up with cool ideas, and then manufacture the most popular, knowing that it has already passed the “will they like it?” test! The A-Frame Cabin was the most recent of such crowd-sourced concepts, released just days earlier.
My step-son and his new wife did not know of my past LEGO history. They did not know that I had been a member of the LEGO Builder’s Club with my son in the 1990s. Or that his LEGO model of the Eiffel Tower had been featured in their newsletter. They did not know that I had authored a software program, LegoShop, to create models on a computer screen in a time before computer graphics, video games and virtual reality had been fully invented. They were unaware of how much time I had spent with a micrometer, reverse-engineering the basic LEGO brick and many other parts to make my virtual models. They did not know, using that program, I had created a Christmas card featuring a LEGO ice castle with Santa and a reindeer. They did not know that I had insisted on visiting LEGO Land during a visit to Malasia. They knew none of this personal LEGO history.
Yet they somehow knew that I would fully appreciate this gift. I’m impressed.
The LEGO Builder’s Club featured my son’s Eiffel Tower as a Member Masterpiece, circa 1992LegoShop, an application that allowed the creation of LEGO models from a library of virtual parts. Some older readers may recognize the window format of early Apple computers.Our 1990 Christmas card, highlighted by virtual LEGOsIn LEGO-Land Malaysia, 2015
I have been a dormant LEGO builder for many years and have not kept up with the latest sets and themes. But the skills to assemble LEGOs don’t go away, and even if they did, the remarkable instructions provided with the kits can be followed in any language, even by builders who, like some of my grandchildren, cannot yet read (but you DO need to know your numbers).
In the case of an enormous set like this one, the instructions run to 333 steps, requiring two books to contain all of the illustrations. The thousands of parts are partitioned into 16 bags, opened one at a time while following the next series of steps to assemble them. The process is much like putting together a jigsaw puzzle, finding the next target pieces, and mating them in correct position with the previous ones. Eventually, the parts that tumble out of the bag are all in place, and I can take a moment to appreciate the growing model.
A view of the partially built cabin. The front door opens into an area with bookshelves, a guitar, and an umbrella stand. The owner appreciates rocks; a geode is prominently displayed next to the record player.
What a pleasure to receive a gift like this. Something created by a LEGO fan and endorsed by a global LEGO community of enthusiasts! I am savoring the construction steps as I go through them, but have recruited the assistance of other LEGO experts. I plan to post photos of the completed project!
Grandsons Arthur and Teddy, reenacting the extinguishing of a dangerous fire with a LEGO firetruck.
Thor's Life-Notes 