Steve Garrity: E.O. Wilson is a leader in the science of biology. This book is a simple read. What I like most about it is that it very effectively conveys Dr. Wilson’s passion for science. His thoughts on what it takes to be a successful scientist resonated with me the most. In describing what it takes to be a successful scientist, E.O. Wilson says that being a genius, having a high IQ, and possessing mathematical fluency are all not enough. Instead, he says that success comes from hard work and finding joy in the processes of discovery. Dr. Wilson gets specific and says that the real key to success is the ability to rapidly perform numerous experiments. “Disturb nature,” he says, “and see if she reveals a secret.” Often she doesn’t, but performing rapid, and often sloppy, experiments increases the odds of discovering something new.
Lauren Crawford: “Richard Stirzaker is a scientist out of Australia committed to finding tools to make farming easier and more productive in third world countries. I love how he talks about what happens when he uses water from his washing machine on his garden and the unanticipated effects: what does the detergent do to the fertilizers and the soil properties? It’s a scientific view of how a garden works.”
Chris Lund: “This is a great introduction to California’s water resources, from where the water comes from to how it is used….particularly relevant today given California’s ongoing drought and the hard choices California faces as a result.”
Paolo Castiglione: “The Drunkard’s Walk’s beginning quote perfectly reflects the author’s thesis: “In God we trust. All others bring data!”. I enjoyed the author’s discussion on how the past century was strongly influenced by ideologies, in contrast to the present one, where data seems to shape people’s actions and beliefs.”
Colin Campbell: “Because of teaching Environmental Biophysics class, all my focus has been on reading An Introduction to Environmental Biophysics. And, although I’ve read it too many times to count, I finally had a chance to study the human energy balance chapter (13) in depth, which was amazing. The way humans interact with our environment is something we deal with at every moment of every day; often not giving it much thought. In this chapter, we are reminded of the people of Tierra del Fuego (Fuegians) who were able to survive in an environment where temperatures approached 0 C daily, wearing no more than a loincloth. Using the principles of environmental biophysics and the equations developed in the chapter, we concluded that the Fuegian metabolic rate had to continuously run near the maximum of a typical human today. The food requirements to maintain that metabolic rate would be somewhere between the equivalent of 17 and 30 hamburgers per day (their diet was high in seal fat). You can read more about the Fuegians here.”
Dr. Gaylon S. Campbell gives a short history on his involvement in the development of thermocouple psychometry:
A psychrometer measures wet and dry bulb temperatures of air in order to determine the relative humidity or vapor pressure.
The Original Psychrometers:
I started working with psychrometers in Sterling Taylor’s lab when I was a sophomore at Utah State University in 1960. A psychrometer measures wet and dry bulb temperatures of air in order to determine the relative humidity or vapor pressure. In a conventional psychrometer, a thermometer bulb is covered with a wet wick and measured to find the wet bulb temperature. A thermocouple psychrometer is used to measure the wet bulb temperature of air equilibrated with soil or plant samples. When a plant is at permanent wilting point, its relative humidity is close to 99%, so the whole range of interest for soil and plant measurements is between 99 and 100% RH. The measurements need to be very precise. To make a wet bulb we couldn’t use a wick. We made thermocouples from 0.001” chromel and constantan wires. We cooled the measuring junction of the wires by running a current through it (cooling using the Peltier effect), condensed dew on the wires through the cooling, and then read the wet bulb temperature by measuring the thermocouple output as the water evaporated. We needed to measure temperature with a precision of about 0.001 C.
Diagram of isopiestic psychrometer used to measure the water potential of plant tissue. Image: 6e.plantphys.net
A New Idea:
The original psychrometers we used in Dr. Taylor’s lab were single junctions mounted in rubber stoppers and placed in test tubes in a constant temperature bath. They were calibrated with salt solutions. Typically, before we could finish a calibration, we would break the thermocouple, so we never got data on soils. I found that frustrating, so had the idea of putting the thermocouple in a sample changer which would hold 6 samples. The sample changer went in the constant temperature bath. When it was equilibrated, we could make 6 readings without taking it out or opening it up. Calibration was done in one try, and we could start running soil or plant samples right away. This was a huge improvement. Our lab was one of a very few who could even make those measurements, and we could make them six at a time. That was about 1964.
Two New Businesses Born:
Later, when I was a graduate student at WSU, I started building soil psychrometers for my own research. Other researchers wanted them, so I taught Marv Sherman, a vet student friend to do the manufacturing, and we sold the psychrometers to whoever wanted them for the cost of his time plus materials. There was a sizable and growing demand when he and I graduated, and no one to carry on. My brother Eric came for my graduation. We asked him if he would like to take over the psychrometer business, and he said yes. We sent him home with some instructions and the materials we had left from Marv’s work. Eric built the business himself and then sold it to Wescor, where he and my brother, Evan became employees. I contributed ideas and helped Wescor grow for a few years, but Eric and Evan were not satisfied there and wanted to start a business of their own. We came up with the idea of them building a laser anemometer, and that was the start of Campbell Scientific.
When we were on sabbatical in England in 1977-78 I had access to a small machine shop and a machinist who was willing to make things for me. The sample changer psychrometers up to this time all had to be used in carefully controlled constant temperature water baths. However, the soil psychrometers that my brother, Eric, sold at Wescor worked fine with no temperature control. I suspected it would be possible to make a sample changer that didn’t need a constant temperature bath. I made some sketches and the machinist made it for me. It had places for 10 samples, had a large aluminum block to hold the rotor with the samples and the thermocouple, and stood on 3 legs. It worked fine without any temperature control.
I showed the new sample changer to my brothers at Campbell Scientific, and they set up and machined a couple of them. CSI didn’t have much interest in selling psychrometers, though, so Decagon began as a way for my children to earn money for college by selling the thermocouple psychrometer sample changer. The name Decagon came both from the 10 people in our family when we started and the 10 samples in the sample changer.
Thermocouple Psychrometry Fades into History:
Decagon (now METER) began selling the thermocouple psychrometer system in 1982 and updated the user-intensive calibration and measurement system to a much simpler one in the mid-1990s. Automation, speed, simplicity, and accuracy soon tipped the scales in favor of a dewpoint technique for measuring water potential, and the system was retired and replaced by a chilled mirror hygrometer (WP4C) in 2000. However, Dr. Campbell believes that thermocouple psychrometers may still have a role to play in measuring water potential. If you’re interested in water potential, check out our water potential pages. It puts many of our best water potential resources in one place and contains sections on theory, measurement methods, and history.
In a continuation of last week’s article “Understanding Avalanches,” we find out what conclusions Dr. Ed Adams and his colleagues in Montana State University’s avalanche studies program were able to make about measuring the thermal conductivity of snow.
In order to study the thermal properties of snow samples, the research team wanted a way to measure thermal conductivity in three directions.
In order to study the thermal properties of snow samples, the research team wanted a way to measure thermal conductivity in three directions. That ruled out flux plates. Thermal probes were an obvious alternative, but they brought a different set of challenges. Snow has a very low thermal conductivity, and as Shertzer explains, “if you add a lot of thermal energy to snow, since it’s very insulative, you’ll tend to raise the temperature. Not only do we want to avoid melting the snow in the neighborhood of the probe, but we want to prevent the probe from artificially inducing the same thermal processes we’re measuring—the ones that cause the crystals to change size, and shape, and orientation.”
Shertzer read an article about measuring thermal conductivity in liquids, where if you add too much heat, you induce convection. “Our situation is similar to that,” he explains. “Heating the needle induces local phase change.” The article gave him some ideas about delivering low levels of heat for a relatively long period of time, and he contacted Decagon to see if that option was a possibility.
Snow barriers in the Alps
Unbeknownst to him, Decagon’s research scientists had just completed a year-long project focused on reducing the contact resistance errors that occur when using the large TR1 needle to measure thermal conductivity in large-grained samples. This made the TR1 needle a good candidate for measuring thermal conductivity in snow. The scientists were excited about modifying TEMPOS firmware to produce a low-power version that would work in snow. The resulting modification has given Shertzer some good data.
“I can definitely say that the anisotropy is there [in the snow samples]. It’s measurable and it’s significant. As the crystals reorient in these depth hoar like chains, the ice network is more conductive than the air in between. The orientation of the chains follows a direction of increased conductivity, and the directions that are perpendicular to the chains tend to decrease in conductivity. Qualitatively, it’s always made sense, and we were just looking for a way to actually relate it to properties like conductivity. Using needles to measure in three different directions simultaneously has given us the ability to measure those properties like conductivity. We expect that this orientation also affects other properties like strength and stiffness.”
Signs of an avalanche
Thermal conductivity studies may ultimately lead to a better understanding of the conditions that cause the snowpack to fracture and trigger an avalanche—and information that may help save lives among the growing number of people who ski and snowboard the backcountry.
Reading through our archives the other day, I came across this article about thermal conductivity and snow. It’s a unique application for a thermal properties analyzer, an interesting story, and something that may ultimately even save the lives of backcountry skiers and snowboarders.
Rich Shertzer, who finished a PhD in the program at Montana State, thinks snow may be unique among natural materials because “the thermal environment it’s exposed to every day can cause pretty remarkable changes in its microstructure.”
When Wired Magazine wrote up Dr. Ed Adams and his colleagues in February 2011, they didn’t refer to them as a team of civil engineers studying granular mechanics. Instead, they named them one of seven teams of “Mad Scientists” and called them “Snow Bombers.”
It’s not hard to find articles about Montana State University’s avalanche studies program. Just describing a typical field study makes for a good story: to investigate real-world avalanche conditions, MSU researchers sit in an outhouse-sized shack bolted to the side of a mountain while colleagues trigger an avalanche up-slope.
But this isn’t just a story about explosions and extreme sports. At its heart, it’s a story about the microstructure of a very fascinating and difficult material. Rich Shertzer, who finished a PhD in the program at Montana State, thinks snow may be unique among natural materials because “the thermal environment it’s exposed to every day can cause pretty remarkable changes in its microstructure.” A cold, sunny day in the mountains can cause significant changes in snow crystals. It can change their size and shape, but more significantly it can cause a directional orientation in snow layers.
Signs of a recent avalanche.
It’s long been empirically understood that avalanches tend to form above “weak layers” of snow. Shertzer and his colleagues are studying how the orientation of snow crystals correlates with weak layers. Most models of granular mechanics assume that the material’s microstructure is randomly arranged. However, snow layers seem to show a regular arrangement.
As Shertzer explains, “Qualitatively, people have known for a while that when you look at certain snow layers, chains of these ice grains seem to be forming. What I was trying to mathematically model is how that might affect the material properties [of snow], including thermal properties.”
Avalanche on Mt. Everest.
In order to study the thermal properties of snow samples, the research team wanted a way to measure thermal conductivity in three directions. That ruled out flux plates. Thermal probes were an obvious alternative, but they brought a different set of challenges. Snow has a very low thermal conductivity, and as Shertzer explains, “if you add a lot of thermal energy to snow, since it’s very insulative, you’ll tend to raise the temperature. Not only do we want to avoid melting the snow in the neighborhood of the probe, but we want to prevent the probe from artificially inducing the same thermal processes we’re measuring—the ones that cause the crystals to change size, and shape, and orientation.”
Read about how the team addressed these problems next week in part 2 of “Understanding Avalanches.”
In a continuation of our popular series inspired by the book, This Idea Must Die: Scientific Problems that are Blocking Progress, Dr. Gaylon S. Campbell relates a story to illustrate the filter paper method, a scientific concept he thinks impedes progress:
There are times when our independent verification turns out to be like the clock and the whistle, and we end up inadvertently chasing our tail.
I remember listening to a story about a jeweler who displayed a big clock in the front window of his store. He noticed that every day a man would stop in front of the store window, pull out a pocket watch, set the watch to the time that was on the large clock, and then continue on. One day, the jeweler decided to meet the man in order to see why he did that. He went out to the front of the store, intercepted the man, and said, “I noticed you stop here every day to set your watch.”
The man replied, “Yes, I’m in charge of blowing the whistle at the factory, and I want to make sure that I get the time exactly right. I check my watch every day so I know I’m blowing the whistle precisely at noon.”
Taken aback, the jeweler replied, “Oh, that’s interesting. I set my clock by the factory whistle.”
The Wrong Idea:
In science, we like to have independent verification for the measurements we make in order to have confidence that they are made correctly, but there are times when our independent verification turns out to be like the clock and the whistle, and we end up inadvertently chasing our tail. I’ve seen this happen to people measuring water potential (soil suction). They measure using a fundamental method like dew point or thermocouple psychrometry, but then they verify the method using filter paper. Filter paper is a secondary method—it was originally calibrated against the psychometric method. It’s ridiculous to use a secondary method to verify an instrument based on fundamental thermodynamics.
Geotechnical engineers use natural material such as soil and rock in combination with engineered material to design dams, tunnels, and foundations for all kinds of structures.
Where the Filter Paper Method Came From:
Before the development of modern vapor pressure measurements, field scientists needed an inexpensive, easy method to measure water potential. I.S. McQueen in the U.S. Geological Survey and some others worked out relationships between the water content of filter paper and water potential by equilibrating them over salt solutions. Later, other scientists standardized this method using thermocouple psychrometers so that there was a calibration. Filter paper was acceptable as a kind of a poor man’s method for measuring water potential because it was inexpensive, assuming you already had a drying oven and a balance. The thermocouple psychrometer and later the dew point sensor quickly supplanted filter paper in the field of soil physics. However, somewhere along the line, the filter paper technique was written into standards in the geotechnical area and the change to vapor methods never occurred. Consequently, a new generation of geotechnical engineers came to rely on the filter paper method. Humorously, when vapor pressure methods finally took hold, filter paper users became focused on verifying these new fundamental methods with the filter paper technique to see whether they were accurate enough to be used for water potential measurement of samples.
What Do We Do Now?
Certainly, there’s no need to get rid of the filter paper method. If I didn’t have anything else, I would use it. It will give you a rough idea of what the water potential or soil suction is. But the idea that I think has to die is that you would ever check your fundamental methods (dewpoint or psychrometer) against the filter paper method to see if they were accurate. Of course they’re accurate. They are based on first principles. The dew point or psychrometer methods are a check to see if your filter paper technique is working, which it quite often isn’t (watch this video to learn why).
Which scientific ideas do you think need to be revised?
Want to develop an appreciation for Gore-Tex? All you need is five minutes in a rubber raincoat. But how do you know whether the North Face knock-off you’ve just purchased in China for a ridiculously low price is Gore-Tex or rubber? If you’re a METER researcher, you dash back to your hotel room and clamp a porometer onto the fabric.
The leaf porometer was designed to measure stomatal conductance in leaves. It’s typically used by canopy researchers to relate stomatal resistance to canopy attributes like water use, water balance, and uptake rates of herbicides, ozone, and pollutants. Yet, from the beginning, Dr. Gaylon Campbell, the porometer’s designer, saw the possibilities: “Give this to someone with only a passing interest in research, a ten-year-old kid for example, and they’ll go around the garden and come back with some really interesting observations,” he said. “There are lots of questions about what loses water and what doesn’t that you can answer with this instrument.”
SC1 Leaf Porometer
Dr. Campbell was probably thinking the questions would be about organic material—but it hasn’t always turned out that way. By putting a wet paper towel on one side of an inorganic material and clamping the towel and the material into the porometer head, you can measure how well water vapor diffuses through the material. Using this strategy, the researcher in China discovered that his raincoat was pretty much impermeable (unlike real Gore-Tex, which is a good vapor conductor). Spotting the fake North Face coat is now a favorite part of METER’s canopy seminar. And the coat is not the only leafless item that has been tested. “People will clamp the porometer on just about anything,” Doug Cobos, a METER research scientist, admitted. He himself grabbed it when a local contractor brought in a sample of some supposedly unique house wrap.
Siding is supposed to protect a house from the elements, but most building codes now require that houses be wrapped under the siding. House wraps provide a secondary defense against liquid water and increase energy efficiency by preventing drafts. As with raincoats, high-performance house wrap needs to repel water and stop wind while remaining permeable to water vapor.
House under construction with protective wrap under the siding.
The practice of applying a sheathing of tar paper under siding is a hundred years old, but in the last fifteen years, high tech house wraps made from polypropylene in combination with a push towards energy efficiency have made the house wrap market big and competitive. Upstart wraps try to gain market share through innovation and the one brought in by the local contractor came along with an outlandish claim. According to the manufacturer’s rep, this plastic wrap would allow water vapor to diffuse out while preventing any from diffusing in. Some builders might have scratched their heads and moved on. Our local man decided to check it out. He brought a sample of the mystical wrap to Decagon. Out came the porometer and a quick scientific study of house wrap was born.
Dr. Cobos tested industry standard Tyvek house wrap along with the great one-way pretender. The results? “The vapor conductance of the new material was basically the same, regardless of which side of the material faced wet filter paper,” Dr. Cobos said. “And, in fact, the material didn’t diffuse well at all. Its conductance was similar to cheap perforated plastic. It didn’t come close to the performance of Tyvek.” Ultimately, the newfangled wrap was retested by the manufacturer and taken off the market.
Probably the porometer’s best and highest use is still in canopy research, but it still gets pulled out to measure whatever seems interesting, organic and inorganic alike. That dovetails with Dr. Campbell’s vision of it as a tool for routine use in canopy studies—and everywhere else. Can you use it on yourself? “Oh sure,” says Dr. Campbell. “People clamp the porometer on their fingers all the time. That’s a quick way to see if it’s working.” He grins. “Maybe you could use it as a lie detector on your kids.”
Dr. John Selker, hydrologist at Oregon State University and one of the scientists behind the Trans African Hydro and Meteorological Observatory (TAHMO) project, gives his perspective on the future of sensor technology.
Dr. John Selker (Image: andrewsforest.oregonstateuniversity.edu)
What sparked your interest in science?
I was kind of an accidental scientist in a sense. I went into water resources having experienced the 1985 drought in Kenya. I saw that water was transformative in the lives of people there. I thought there were lots of things we could do to make a difference, so I wanted to become a water resource engineer. It was during my graduate degree process that I got excited about science.
What was the first sensor you developed?
I’ve been developing sensors for a long time. I worked at some national labs on teams developing sensors for physics experiments. The first one I developed myself was as an undergraduate student in physics. I was the lab instructor for the class, and I wanted to do something on my own while the students were busy. I made a non-contact bicycle speedometer which was much like an anemometer. I took an ultrasonic emitter, trained it on the tire, and I could get the beat frequency between emitted sound and the backscatter to get the bicycle speed.
What’s the future of sensor technology?
Communication
Right now one of the very exciting advances in technology is communication. Having sensors that can communicate back to the scientists immediately makes a huge difference in terms of knowing how things are going, making decisions on the fly, and getting good quality data. Oftentimes in the past, a sensor would fail and you wouldn’t know about it for months. Cell phone technology and the ability to run a station on a few AA batteries for years has been the most transformative aspect of technological development. The sensors themselves also continue to improve: getting smaller and using less energy, and that’s excellent progress as well.
What often happens is that you install a solar sensor, and then a leaf or a dust grain falls on it, and you lose your accuracy.
Redundancy
I think the next big thing in sensing technology is how to use what we might call “semi-redundant” sensing. What often happens is that you install a solar sensor, and then a leaf or a dust grain falls on it, and you lose your accuracy. However, if you had a solar panel and a solar sensor, you could then do comparisons. Or if you were using a wind sensor and an accelerometer you could also compare data. We now have the computing capability to look at these things synergistically.
Accuracy
What I would say in science is that if we can get a few more zeros: a hundred times more accurate, or ten times more frequent measurements, then it would change our total vision of the world. So, what I think we’re going to have in the next few years, is another zero in accuracy. I think we’re going to go from being plus or minus five percent to plus or minus 0.5 percent, and we are going to do that through much more sophisticated intercomparisons of sensors. As sensors get cheaper, we can afford to have more and more related sensors to make those comparisons. I think we’re going to see this whole field of data assimilation become a critical part of the proliferation of sensors.
What are your thoughts on the future of sensor technology?
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Six short videos teach you everything you need to know about soil water content and soil water potential—and why you should measure them together. Plus, master the basics of soil hydraulic conductivity.
Gaylon Campbell’s first experience with environmental measurement came in the lab of Dr. Sterling Taylor at Utah State University, where he was asked to make water potential measurements in order to understand plant water status. What he learned with Dr. Taylor became the start of four scientific companies and gave Dr. Campbell the tools and the confidence to become one of the world’s foremost authorities on physical measurements in the soil-plant-atmosphere continuum. Here’s what Dr. Campbell had to say about his association with Dr. Taylor:
Who was Sterling Taylor and why is he considered one of the Founders of Environmental Biophysics?
Sterling Taylor was professor of Soil Physics at Utah State University. He did his undergraduate work at what was Utah State Agricultural College, and earned his PhD at Cornell University. He worked on both theoretical and practical problems in soil physics. His practical work focused on research in the area of plant-water relations and irrigation management. Dr. Taylor worked out water potential limits for both maximum and reduced growth rates of crops. The irrigation limits tables that he put together are still used in today’s handbooks. His theoretical contributions were on linked transport and applications of non-equilibrium thermodynamics to soil physics, which he was working on at the time of his death. Dr. W. H. Gardner, a soil physicist of the time, called the amount of work Dr. Taylor and his students did “unparalleled” and noted that attendees at regional conferences often had to carry Taylor’s “weighty reports” home as overweight baggage.
Attendees at regional conferences often had to carry Taylor’s “weighty reports” home as overweight baggage.
What was your association with him, and how did he influence your life and your science?
Sterling was a kind of second father to me and to many other young scientists. He loved to help boys and teach them what their potential was. At that age, I didn’t have any idea that I could do anything in science. The first assignment he gave me was to set up an experiment to measure the simultaneous movement of salt and water in soil. I had no idea what I was doing, and it was a challenging project. It would be challenging for me to do it right now! But he’d give me ideas about how to do the next thing, I’d try to do it, and eventually I got some data that he thought was useful. He did some analysis of it, and that’s how I learned to measure electrical conductivity and salt concentration in water and soil. Sterling’s lab is also where my brother Eric and I learned how to make thermocouple psychrometers and other instruments for environmental measurements. Those insights led directly to the start of Wescor and Decagon. Campbell Scientific, Juniper systems and others eventually came from those beginnings.
Dr. Taylor was also a very patient man. He made a precision constant temperature bath out of an old washing machine. It had an agitator in the middle to stir the water while cooling it with coils around the outside of the tub. It was a wonderful setup, and he took a lot of pride in how well it worked. He came into the lab one day while I was making some modifications to it. I was drilling a hole through the outer jacket around the Freon(™) coils where the refrigerant ran. He said, “Now be careful if you’re drilling holes through that thing so you don’t hit the coils”. And I said, “Yes, I’m being careful.” But I wasn’t. The coils were a couple of inches apart, and I thought, There’s no way I’m going to hit one. I didn’t even get a ruler. I just eyeballed it, drilled a hole, and hit the tube dead on. I couldn’t have hit it more perfectly if I’d measured as carefully as I could. All the refrigerant came hissing out, and I thought he would hear it over in his office. He probably did hear it, but he didn’t come out to see what was going on. One of the hardest things I ever did in my life was to go in and tell him I’d drilled a hole in his refrigerant tube. He just said, “Well…I guess we’ll have to get some new refrigerant.” He was just patient, and knew how to work with young people.
I made a career choice to be a teacher and have students.
But that wasn’t the only way he influenced me. As it came time for graduation he gave me some advice that had an enormous impact. Once when I was trying to choose between soil physics and medical biophysics he said “do you want to be a little duck in a big puddle or a big duck in a little puddle?” I decided on the little puddle. On another occasion, I was wondering what kind of soil physics position would be best. One of his former students had gotten a job at an experiment station near Kimberly, Idaho, and I thought that would be ideal. He observed, “Those can be fun jobs, but if you go to a position like that you just don’t have any offspring.” That resonated with me, and I thought, “I would like to have offspring.” So I made a career choice to be a teacher and have students. It was wonderful to have had that kind of advice at that critical time.
What do you think we missed because he died so early?
It’s interesting to think about scientific contributions and other types of contributions people make. One of my sons gave me a book of science cartoons, and one of those cartoons shows a couple of scientists talking together. One of the scientists says to the other, “Isn’t it sad to think that everything we come up with now will be disproved in 20 years?”
It just shows you what a transient thing our work is. We think it’s so important, but the important contributions that Sterling made were the numbers of people that he influenced so profoundly. I’m not the only one he was a second father to. Sterling Taylor had a huge family of students. Many went on to prestigious institutions like CalTech (California Institute of Technology), making important contributions over their careers. And they trace it back to Sterling’s influence on them.
How can scientists today emulate the great man that he was?
I think it would be to not take science so seriously but to take interactions with their fellow travelers seriously. There is a quote by Clayton Christensen from an article in Harvard Business Review on how to emulate what Sterling Taylor was. Christensen says, “I’ve concluded that the metric by which God will assess my life isn’t dollars but the individual people whose lives I’ve touched. I think that’s the way it will work for us all. Don’t worry about the level of individual prominence you have achieved; worry about the individuals you have helped become better people. This is my final recommendation: Think about the metric by which your life will be judged, and make a resolution to live every day so that in the end, your life will be judged a success.”
On May 25, 2008 NASA’s Phoenix Lander successfully landed on the surface of Mars and used a robotic scoop arm to deliver regolith samples to the suite of instruments on the deck of the Lander—with one exception. The Thermal and Electrical Conductivity Probe (TECP), designed by a team of Decagon (now METER) research scientists, was mounted on the knuckle of the robotic arm and made direct contact with the regolith. It measured thermal conductivity, thermal diffusivity, electrical conductivity, and dielectric permittivity of the regolith, as well as vapor pressure of the air.
But, that’s starting at the end of the story. The fact is that TECP almost didn’t get started. After seeing a thermal properties needle at the American Geophysical Union meeting in San Francisco, Mike Hecht (project leader on the Mars Environmental Compatibility Assessment (MECA) instrument suite) encouraged his colleague Martin Buehler to call Decagon (now METER) to see if we’d be willing to participate in the Phoenix Lander project. When Martin called one Friday afternoon, announcing that he was from JPL and wondering if we would be willing to fly our sensor on the Phoenix Lander, I was instantly intimidated. I knew JPL was associated with NASA, and I couldn’t imagine why they would be calling Decagon. I always thought there was a fundamental relationship between NASA and Lockheed Martin, Northrop Grumman, and other major companies that did NASA work. I told him that Decagon, which was much smaller in those days, didn’t have the capacity to develop instrumentation for space flight. He suggested they come up for a visit and at least consult with us on what they would need to do to obtain this measurement. The following Monday, we were talking Martian science and inexorably hooked on the idea of joining the team.
I knew JPL was associated with NASA, and I couldn’t imagine why they would be calling Decagon.
Deciding to put one of our sensors on Mars did nothing to lessen the intimidation factor. But, working with Mike and his team at JPL/NASA taught us that doing amazing science can be an inspiring and collaborative effort. I’d always imagined NASA as a group of uber-scientists and engineers sitting in glass offices dreaming up and executing great projects that would be impossible for mere mortals. The reality is that sending something to Mars and having it do real science requires the combined effort of thousands of smart, dedicated people who are not that much different from the rest of us.
This idea was really brought home when we finally visited JPL. Although the things they were doing were amazing and on a much grander scale, they weren’t that much different from the things we do at Decagon. They had testing facilities, development facilities, production facilities, and support personnel all working together on projects, just like us. However, the projects were pretty amazing. We watched the robot arm being tested in a lab for the ability to dig martian soil analogs. We observed an ice probe working in a 55-gallon drum trying to prove it could melt its way down through the thick Martian polar ice caps. We were mesmerized by prototypes of Mars rovers being programmed and executing maneuvers on Martian surface analogs.
It was fun to discover who the Jet Propulsion Lab is and how enjoyable it is to collaborate with people that are thinking about new applications of technology. This collaboration also benefitted METER’s thermal properties instrument because the mathematical models we developed for Mars made this sensor much more accurate and effective. The Mars project expanded both the depth of our understanding and the breadth of our perspective. Even so, it was fun to find out that scientists who work at JPL have to put their pants on one leg at a time, just like all of us.
Watch this virtual seminar where Dr. Mike Hecht talks Mars, poetry, and Decagon’s (now METER’s) involvement in the Mars Phoenix Lander Mission.
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Chris Chambers is the primary technical support scientist at METER. Deep within the recesses of his office, there is a collection of scientific instrumentation we like to call the “Museum of Horrors”. It showcases the many instruments that have been mangled and destroyed over the years by insects, animals, or the environment.
This serial cable melted when it got too close to a sample heating oven.
We get a few instruments back every year that are burned up in a fire, chewed up by rodents, and occasionally we get one that’s been exploded by lightning. We interviewed Chris to find out how to prevent scientific instrumentation from being damaged or destroyed by these types of natural disasters.
The single most important thing you can do to prevent damage from animals is to protect your cables. You can protect your cables with cable armor, electrical conduit, or PVC pipe. Even better is to place cables in some type of conduit and then bury it. Keeping things tidy around the data logger and avoiding exposed cables as much as possible will go a long way toward preventing animals and insects from ruining your experiment.
A retired ECH2O10 that was hit by a shovel.
Lightning:
Lightning is not as big of a danger on METER loggers as it is with third party loggers (read about logger grounding here). Where we typically see people run into problems with lightning is when they have long lengths of cable between the data logger and sensor. Long cable runs act like lightning harvesting antennae. The best thing to do is to keep the cables shorter and do not spread them out in lots of different directions.
We have a few instruments every year that get burned up in fires, but there is not much you can do about this hazard except for watching for reports of encroaching fires that may be in your surrounding area and evacuating important instrumentation.
The worst killer of data loggers is flooding. We have a lot of customers that try and bury their loggers, and that’s generally a terrible idea. Unless you can guarantee the logger will be waterproofed and put some desiccant inside the box, it will probably end badly. There are a few scientists out there that have done a really good job of waterproofing, but they generally spend almost as much effort and money waterproofing as they do purchasing the actual logger.
There’s always going to be some risk to your scientific instrumentation because you’re installing it outside, but hopefully, these tips will help you avoid disaster and keep your system out of the museum of horrors.
