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Posts Tagged ‘mojave desert’

Soda springs palms

Palms planted at Soda Springs on Zzyzx Road

In this blog, I have been reporting on activities we did during the Mojave field study that have to do with chemistry and the elements, but since the purpose of the field study was to look at Earth analogs for possible Martian organisms, much of what we did is and will be recorded on my other blog site (www.spacedoutclass.wordpress.com). I will do much more with that site in late July as I prepare to teach astronomy this fall. At that point, the “wordpress” portion of the URL will be eliminated and the site will go “live” so to speak. I have many topics that need to be written about, including more on the Mojave experience.

Preparing the weather balloon

Chris McKay (in denim jacket) and CSU students preparing the weather balloon for launch.

But meanwhile, our last day in the Mojave was Friday, March 23. We prepared and launched a weather balloon, then each group presented their interim reports on the results of the study. I helped Mary Beth talk about the geology and soil chemistry analyses, and I also presented the 3D model of the test soil sample I worked on with Geoff Chu and his group (more on this in the other blog). I plan on having students at Walden School take the grayscale images and the actual altitude data and create 3D models and textures for each crust site which can be manipulated online.

I also took the opportunity to interview Dr. Rakesh Mogul, who was with CSU and is the organizer of this event, but is now moving to the NASA Office of Planetary Protection. He talked about the protocols that NASA uses to determine now clean a space probe needs to be so as not to contaminate a planet with our microorganisms and so as not to mess up our science results when looking for life.

Weather balloon

Weather balloon after launch.

Once I had packed up my video equipment and other gear, I drove back to Utah, stopping in Las Vegas to drive through on the Strip. It has been about 15 years since I’ve actually done this, and it’s changed quite a bit – gotten larger, more crowded, and not very enticing for me, since I don’t gamble (I’ve taken too many operant conditioning classes in college to ever do that). It was a long drive back, but the trip was very much worth it. All told, I took about 15 hours of video, which will now take some time to capture and edit. I hope to do at least some of it (the interviews) this summer.

I wasn’t home for long (about four days) before I flew out to Indianapolis for the annual National Science Teachers Association conference. Much of what I did there was related to space science and astronomy (including attending a luncheon where an astronaut spoke; the awards ceremony for this year’s Mars Education Challenge, where I was asked to be the official photographer while Bill Nye introduced the winners and handed out the awards; and my own presentation on the SOFIA Airborne Astronomy Ambassadors program). However, I did attend a number of excellent sessions that were related to chemistry and the elements.

Above the clouds

Above the clouds on the way to Indianapolis

On Thursday, March 29 I had to take the local buses from my motel out by the airport to downtown, and I was slightly late for the bus and had to wait 30 minutes for the next one, so I was a bit late getting into the conference. I went to the first session I could find in the booklet that was near where I was standing in the convention center and that sounded interested. It was a presentation on an activity that introduces the periodic table to students. The room was packed and I had to sit on the floor while the presenter talked. Something about him looked familiar, and suddenly I realized that the presenter was John Clark, a fellow SOFIA AAA. I had seen his photo on the discussion board.

John Clark and the SOFIA team

John Clark and the SOFIA team from NASA Ames and the SETI Institute

His activity is done early on in a chemistry class, and involves handing 3 x 5 index cards to each student. They decorate their card, choose a name for their personal element and a symbol, then decide on properties of their element that describe their own personalities from a list, such as “science nerd” or “techy” or “drama king.” Other properties could be chosen from a list, such as number of electrons, etc. The students group themselves into “element” families according to the properties they selected, such as the colors they choose. From this they create a type of periodic table of their class, which the class as a whole has to discuss and justify. Not only does this get the students thinking about elements, properties, symbols, and other aspects of the periodic table, but it helps the teacher get to know the students better.

cloud chamber

Cloud Chamber

I also attended a session by April Lanotte on how to build your own cloud chamber, which worked quite well. I’d tried to do this with a kit in the past, but could never get it to work. The secret is to not allow any air in or out as the internal air must be saturated with alcohol fumes and cooled with dry ice before stray cosmic rays can be seen or radiation from an alpha or beta source as vapor trails in the alcohol gas. She had built hers out of an aquarium that was carefully sealed. She also showed us amore sophisticated digital cosmic ray counter. She is an Einstein Fellow this year, and I also attended a number of sessions on that program and on the Presidential Award program.

Another session I attended was by L. Diener (I didn’t catch her first name) on the science of chocolate. Since my students and I just finished videotaping a tour of Amano Artisan Chocolates in our town (more on this later), I was interested in attending and she presented a simple activity about solubility and chocolate. Take a piece of chewing gum, such as candy coated Chiclets, and chew it for a few minutes until the flavor begins to decrease. At this point your saliva has dissolved all the sugars and flavors that are water soluble. Then take a Hersey’s kiss and chew it with the gum. Suddenly the remainder of the gum dissolves in your mouth, because the chocolate’s cocoa butter will dissolve the remaining fat soluble portions of the gum. But as soon as the chocolate has melted and dissolved in your mouth, the gum will start to re-solidify, although there will be less of it. It can be a big gross to feel this happening in your mouth, but it is a great way to talk about food science and how various substances do or don’t dissolve in each other.

David Black by the NSTA sign

David Black by the NSTA sign, Indianapolis Convention Center.

It was a busy conference. I walked through the dealers’ room and priced sensors and probeware for both the Vernier and Pasco systems, hoping that I’ll get some grant money to be able to use sensors with an iPad. I ran into old friends, such as Martin Horejsi (we were on the same flight going to Indianapolis, as he has to fly to Salt Lake from Missoula to pick up most connections) and Eric Brunsell. They were the only people from the Solar System Educators Program that I saw. But I did get to know some of my new associates, the SOFIA AAAs.

Downtown Indianapolis

Downtown Indianapolis

 

I did get a chance to do something quite unusual. I was selected (how I don’t know) to sit in on a panel discussion on NSTA’s The Science Teacher journal and on the NSTA website. We were given a nice luncheon, then were asked a series of questions by Tyson Brown, whom I had known before back when I was doing the NASA Explorer Schools program. It was a fascinating discussion, and I put in a plug or two for Martin and Eric’s column (Science 2.0). There were several people in the back of the room writing notes, and one looked familiar. Once we opened up the journal and started going through it, I realized who he was – Steve Metz, the editor. I have decided that I really must submit an article as soon as possible. But my schedule has become so crazy that I’m not sure when that will be or which of several possible topics to write on. For our participation in the panel, we also received a $50 certificate to use in the NSTA bookstore.

Dealer room at NSTA conference

Dealer room at the NSTA conference. Eric Brunsell is in the black shirt at the left of the photo.

Much of what I did and learned will be written (eventually) on the other blog site, as it is more related to astronomy than chemistry. There is, however, one other presentation I went to that I want to discuss here, and that was a lecture on ingenuity and creativity given by author David Macaulay. He is writing a book on how ingenuity has brought about marvelous ideas and inventions through the ages, and he basically walked us through his own creative process in developing the book. When I first started teaching in California, I taught world history for several years and used films based on his books Cathedral and Pyramid in my classes. They were very well done, and he has since created such books as The Way Things Work.

Between this lecture and the panel discussion luncheon, I did a lot of thinking while waiting for the bus on Sunday morning (only to find it doesn’t run on Sundays, so the motel’s shuttle van driver took me downtown instead). But while waiting, I thought of several ideas for books and series of books I could write for NSTA Press, such as how to use authentic science data in the classroom. I’m doing more of this all the time, and many of the sessions I chose to attend were based on real data analysis. I realize that in some ways what I am doing is unique, since I blend science and computer graphics/3D animation technologies. Yet the one session I attended Sunday morning was all about this – the art of science, and Randy Landsberg of the U. of Chicago showed examples of collaborations between artists, the Kavli Institute for Cosmological Physics, and the Adler Planeterium, including an incredible animation taking the viewer to the edge of the universe and another showing cosmic ray showers from the Pierre Auger data. I scribbled notes as fast as I could, and I still need to check up on all the possibilities. It was invigorating to see that others are pushing the edge and blurring distinctions between art and science, which is one of my goals as well.

It was an incredible conference. I was very involved, learned much, brought back many ideas, and made good connections.

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Soil Samples Context

Sites for our soil samples: Site 1 was on the side of a hill (where people are gathered) and Site 2 was in the wash at the foot of the hill.

On my fifth day at Zzyzx Road (Thursday, March 22) we turned our attention to the soil mechanics and chemistry of the Mojave National Preserve. We traveled with soil experts from the Natural Resources Conservation Service to conduct several digs of soils typical of this area.

Soil trench 1

Soil Trench 1. The lime layer is about 6 inches down.

 

About one mile off I-15 along the south side of Zzyzx Road we climbed a low hill and dug a small trench into the soil about three feet deep, keeping the upper slope sharp so that we could look at the soil profile. At first glance this hill would seem to be volcanic (that’s what I thought as I drove past it coming in) but it had a mixture of rocks carried down to it from uphill, and the hill itself is probably an erosional remnant. Across the freeway we could see similar layers, mostly ancient, tilted limestones.

Soil site 1 group

Group at Soil Site 1

Digging down, we found fairly well sorted layers, some containing mostly sand, others small pea gravel, etc. About six inches down was a hard white layer that looked almost like chalk – which is what it basically turned out to be, as it fizzed quite nicely with a simple acid test. As the limestone uphill erodes, it dissolves into the runoff water and is carried downhill and soaks into the ground, turning into calcium oxide. But the rains here are so infrequent that the lime doesn’t soak in further than about six inches before it deposits out, much in the same way cave formations precipitate from solutions in caves. This hard, alkaline layer combined with low humus and low rainfall makes this soil inhospitable to most plants, but there are a few that manage through some remarkable adaptations.

Soil trench 2

Soil Trench 2, in the wash near Zzyzx Road.

My personal favorite is the ubiquitous creosote bush. Each bush is an island of life, with small plants growing in the decayed material under the creosote’s shade. The creosote leaves are small and intensely green, covered with a pungent waxy sap that prevents evaporation. This chemical is extracted and used to coat railroad ties to prevent them from rotting. Its most amazing adaptation is the root system, which extends into the soil through the lime layer and down about 12 feet, spreading out underneath. This is why creosote bushes don’t grow in clumps but are separated by about 12-20 feet on average. This huge system of fine roots is able to draw out any moisture that exists in the soil. We saw the roots extending down through our profiles, forming an important part of the desert ecosystem.

Creosote bush

Creosote Bush at Intermediate Crust Site

We also used a backhoe to dig a trench into the soil in a nearby wash (which had some young soil crusts beginning to grow). We used soil sieves and water to separate the materials and get a rough estimate of the abundance of sand, silt, fine pebbles, and rocks. This data is being used to map the soils of the Mojave Preserve, much as geologists have already mapped out the rock outcroppings. On a geological map, the valley floors are simply listed as “unconsolidated fill.” These studies will help add more detail to the maps.

I find myself drawing comparisons between the soils here and what I grew up with in the Sevier Desert of western Utah, part of the Great Basin province. My hometown of Deseret lies on an ancient delta of the Sevier River, and the river runs through it (right past our house).

Millard County features

Features along the Sevier River drainage system in Millard County, Utah.

In the past, before being used for irrigation, the river would see large spring runoffs since it drains a large area of central Utah. In fact, if you stand on the ridge at the top of Bryce Canyon National Park, everything in the canyon and beyond drains into the Paria River and eventually into the Colorado and to the Sea of Cortez. Everything behind the ridge drains into the East Branch of the Sevier River. This ridge is a watershed divide. The West Branch drains the back side of Cedar Breaks and Panguitch Lake. The river then travels along U.S. 89 to Yuba Lake, where it hooks through Leamington Canyon and then southwest past Delta to the Gunnison Bend Reservoir and on through Deseret, eventually ending in Sevier Lake, which now is mostly dry.

Before irrigation, the river cut a series of distributaries as it left the bluff north of Delta, and it was a large runoff that cut a new channel one mile north of the first settlement of Deseret, leaving the town high and dry. The Old Mud Fort is actually on the north side of the old settlement. The town was mostly abandoned, until my own ancestors came from the area at the mouth of Zions Canyon to resettle Deseret at its present location. Yet the river is still not entirely tamed. In 1983, a very large runoff caused a dam north of Delta to burst and Deseret was flooded. I spent much of the remaining summer cleaning up the mess. We had an even bigger runoff last year (2011) but we’ve learned a few lessons from the 1983 flood and were able to make room for all the water, even allowing some of it to flow unused down to Sevier Lake.

All this runoff took any minerals from the central Utah region, including large salt and gypsum layers near Richfield and Salina, and deposited them in the soils as the water spread out, leaving high salt and alkali content. I’ve tested the soils around Deseret and my father’s farm and they average a pH of about 8-9 (in some places almost 10). The alkali creates white-rimed hardpans in places where nothing will grow and only alkali bees can live. The Sevier River water has about the same pH – after being passed and drained through farms all along the river, it is very brackish by the time it reaches us. It’s a miracle that anything can grow besides greasewoods and rabbit brush, yet with crop rotation and fertilizers, along with drainage channels and an excellent irrigation system of canals and ditches, we are able to grow good crops of alfalfa, corn, and grain.

Delta to Deseret Utah

Area around Delta and Deseret, Utah.

But the soil chemistry does exact a toll. The ground water aquifers that we used for drinking water not only had a high level of natural fluoride in them (we’ve got tough teeth) but were found to have high levels of arsenic salts as well. No one knows the original source of the arsenic, just that it’s there in the groundwater. New wells had to be drilled that went deeper, beyond the contaminated zone, and a town water system installed instead of individual family wells.

My chemistry students sometimes wonder what chemistry has to do with them. I point to the example of arsenic in my groundwater as just one way that the elements have affected me.

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Chlorophyll analysis

Dr. Rakesh Mogul and students conducting chlorophyll analysis of soil crust samples using IR absorption

On our fourth day at the CSU Desert Studies Center on Zzyzx Road, we continued our analyses of the biological soil crusts and began to put together the results of our studies. The CSU students extracted chlorophyll from the crusts and the soils underneath, then measured amounts by looking at infrared absorption lines at several wavelengths that are characteristic for chlorophyll.

GPS data for soil samples

Mapping the GPS coordinates for our samples

 

I helped Mary Beth start mapping out the trends we saw in the various chemical analyses of the soils at the three main sites. She did most of the work, looking up geological maps of the area around Baker and the various types of rock outcroppings and unconsolidated valley fill deposits, then located all our sample sites from the GPS coordinates we’d recorded on Monday and created gradient arrows across the maps showing how the various elements and compounds trended between locations.

geologic map of area

Charting soil chemistry changes onto a geological map along Kelbaker Road

Most of the trends were to be expected, but a few were surprising. For example, there was more aluminum and calcium in the soil at the low density site than at the other two. We joked that all the pop cans left as trash scattered around the low density site (which was near Baker) might have been the source, but of course that would be impossible – it would take a huge number of cans, completely oxidized away, to leave any kind of aluminum residue. So we looked at the maps for possible sources. This site was in more of a playa lake bottom and probably has more clay in the soil (which we can confirm with the soil mechanics group), and clay is an aluminum silicate. The calcium could come from nearby limestone deposits.

Desert Studies Center

CSU Desert Studies Center on Zzyzx Road in the Mojave National Preserve. Baker, CA is in the distance.

Overall, our project is a good example of how field research is carried out –you start with a question and a site to test it at, consider the possible ways to isolate the data you need from all the other variables in the environment (such as pop cans), come up with experimental procedures and protocols, then travel to the site, collect the data, conducting both field and laboratory analyses, then analyze the results and try to make sense of it all. It isn’t quite the formal scientific method we teach in middle school science classes. Often the statistics aren’t as strong as you would like because you’re using ANOVA (analysis of variance) or MANOVA (multiple analysis of variance) techniques. Since many different conditions are being tested, and you have to see how they all stack up and compare, often there are only a few data points per data set.

Soda Lake playa

Soda Lake playa in the Mojave Desert

It’s not as neat and predictable and controllable as a lab experiment, but it’s a lot more fun. For us, our biggest problem was trying to draw conclusions from the tests we ran, which were more qualitative and less reliable than we would like. The one test kit was designed for gardeners to use, and had test strips that only showed low, medium, and high results without any kind of ratio data. We also had some more individual tests for specific elements and compounds (such as chlorides or sulfates) that were a bit more numeric (at least they had scales) but not much more reliable. Often when we tried to do a sample a second time, the results weren’t very consistent. So we’d have to run the test a third time, or try to filter the soil better, etc. For our final results, we can’t rely on these inaccurate field tests. We’ll have to send the samples in for detailed lab analysis to find out the precise percentages of different elements. It will be interesting to see if our field results match up.

Borax stripes

Stripes in salt falt where borax and soda have been scraped up.

I also took the opportunity to climb a low hill behind the lab with my camera equipment to get a good look at the surrounding desert. From up there, I could see back to Baker and I-15 in one direction and toward the Kelso Dunes and deeper into the Mojave National Preserve in the other direction. This research station was originally a way station on the overland stage route, then eventually became a center for borax mining. On the other side of the hill, parallel trenches can still be seen where the borax powder was scraped up and piled, to be shipped out by the famous 20-mule teams. This is the low point in this valley and a salt flat/playa lake surrounds the Soda Springs area. It probably looks pretty barren and inhospitable to most people, but this is the kind of scenery I’m used to growing up in the Pahvant Valley of western Utah, with Sevier Lake and frequent evaporated alkali deposits to the west of my father’s farm. The weather has gradually warmed up from the freezing wind that greeted me on Sunday night.

borax minerals

Borax minerals and a model of the 20-mule teams that hauled the borax.

The commons room has some displays showing borax crystals and brief descriptions of how the mining was done, as well as the natural history of the station with local flora and fauna. The boron compounds (usually borates such as sodium and calcium borate) are generally known as borax, and have many uses. Borosilicate glass is highly heat resistant and is used in chemical lab ware, where we know it as Pyrex. It is also being used to contain and store radioactive wastes; since glass is highly stable chemically, the spent nuclear fuel rods are mixed with the glass in the form of marble-sized spheres or as sheathed glass columns. Borax also helps to extend laundry detergent, and provides the green color for fireworks.

History of borax mining part 1

The history of borax mining, part 1

I use borax to create the cross-linked polymerization when I make “gak” in my chemistry classroom. Here’s the recipe: take two paper cups. In one, fill it about ¼ full of warm water and ¼ full of white glue, plus a little food coloring. In the second cup, fill it about 1/3 full of warm water and about 10-15 grams of borax powder. Stir it up well, then mix the two cups together and keep on stirring. At first it will be a sticky mess, but in a minute or so the cross-linking between the glue strands will begin and water molecules get trapped in the borate links, making the whole thing into a fun, gloopy concoction that can be kneaded and molded.

I am including here two photos of the poster that describes borax mining, which you can read to find out more of the history. I’ll create a dedicated post later on going into more detail after I do some more research.

Timeline for Soda Springs Station

Timeline for Soda Springs and Zzyzx station

History of borax mining part 2
History of borax mining, Part 2

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Lab at Zzyzx

Lab Building at the Desert Research Station at Zzyzx Road, CA.

On this third day of our research project in the Mojave Desert, we did a series of tests on the biological soil crusts and soil samples we collected yesterday at three sites along Kelbaker Road near Baker, CA.

Parag and Rakesh

Parag and Rakesh demonstrate extraction protocols

The laboratory building at the Desert Research Station is set up with standard equipment for chemical and biological tests, including flasks, test tubes, Bunsen burners, sinks, a fume hood, etc. Most of the detailed equipment and supplies was brought by Rakesh Mogul and the other scientists working on this project, including a centrifuge, a spectrometer, pipettes and pumps, and test kits and reagents for the extractions and analyses we’d be doing.

Interior of lab

Inside the lab building at Zzyzx Road

The students and scientists had set up a series of protocols for the tests and a plan of attack for how to identify each sample. First, a group were taking samples of the crusts at each location and extracting the DNA from them. Each time, the scoop was sterilized with a Bunsen burner. The solution was then centrifuged to settle out the non-dissolved portions. Another group was at work using polymerase chain reaction techniques to increase the DNA yield so that the final sequencing could be done in a specialized lab. We’ll have the lab look at the specific species in the crusts, including the cyanobacteria, fungi, lichens, mosses, and archaea present in these symbiotic communities.

Extracting DNA

Extracting DNA from the biological soil crusts

Parag Vaishampayan worked with a group to extract ATP (adenosine triphosphate), which will give us a measure of metabolic rate in the crusts at each site. We sampled not only the crust itself but the soil directly underneath each sampled crust, and will look at ATP of the crust compared as a ratio to the ATP in the soil. The hypothesis is that the healthier crust will have a higher ratio.

Extracting ATP

Testing for ATP

Meanwhile, the soil itself was analyzed. Mary Beth Wilhelm and Liza Coe used a soil test kit to look for trace elements in the soil, such as aluminum, iron, chlorine, and magnesium. I helped do some of this analysis, since my background is in chemistry and geology. Rosalba Bonaccorsi, Ruben Hovanesian, and Leonard Bacon separated the soils using sieves to find the relative sizes of particles and materials at each site.

Soil tests

Testing the soils chemically

A final group of pre-math teachers developed a series of statistical tests to look at results of all these tests, including some ANOVA (analysis of variance) tests, which I vaguely remember from my masters degree program.

Pipette instruction

Instruction on pipette techniques

We got quite far with the tests today – it helps to have a group of people who are experienced and work well together. Although they come from all over the California State University system, the students are all in their second year in the program and know what to do and what each other’s strengths and weaknesses are. We all helped out where we had experitise. It was fun to see what college students can accomplish. We have one major remaining test for tomorrow: chlorophyll extraction and spectral analysis.

Statistical tests

Allison and Kristen working on statistical models

I also talked with Geoff Chu, Paul Mans, and Ryan Piaget from NASA Ames who are developing a prototype rover built from a commercial off-the-shelf RC car, with video camera provided by an Android phone controlled from a laptop over a local network. Motor servos are controlled by an Arduino brick. The point of this rover is to analyze the soil crusts remotely without having 20-odd people stomping around on them. The rover will be equipped with a stereoscopic IR camera that can read 3D depth, along with an RGB camera. My goal is to take the height data from the IR camera and convert it into a grayscale heightmap of the various crust locations, then turn the heightmap into a 3D model in Daz3D Bryce. The RGB photo will be mapped over the top of the model as a texture. Ultimately, the model can be uploaded to an online app where people can rotate and explore the crusts themselves.

Geoff and Paul

Geoff Chu and Paul Mans working on the RC rover

We had a preliminary results meeting after supper to look at what we have so far. The ATP analysis was not consistent across sites, possibly because the results changed as the day warmed up, but we’ll send the samples to labs for more accurate results.

Review session

Review session for today's results

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