Chemical Education Today
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News from Online: Digging Up Earth Day Resources by Bernadette A. Caldwell Photo: Lynn Betts, USDA NRCS
Soil is both familiar—encountered through child’s play and gardening and cleaning—and mysterious—often invisible under crops or grass or pavement, yet capable of nurturing plant and animal life. Intrigued by this year’s focus on soil for Chemists Celebrate Earth Day, I went online to see what I could unearth about soil related to chemistry. While the ensuing journey is not comprehensive, many Web sites cataloged here could be profitably used to incorporate soil science and soil chemistry into your teaching materials for Earth Day and beyond. General Information To gain some background understanding, I visited the soils education home page of the U.S. Department of Agriculture (USDA) at http://soils.usda.gov/education/, which features links to many additional internal and external sites. Geared primarily to K–12 students (with the bulk of activities appropriate for K–8 students), the information here ranges broadly from straightforward geology, biology, and soil classification to more whimsical soil songs and soil poetry. In a similar vein, the soil science education home page at NASA (http://soil.gsfc.nasa.gov/links.htm) provides many useful links for teaching soil science to elementary and middle school students. For a more sophisticated overview, visit the International Soil and Reference Information Centre, http:// www.isric.nl/ and follow links to About Soils where you’ll find basic concepts, a glossary, a view of ISRIC’s World Soil Museum (with a virtual tour under construction), and a tutorial and picture gallery on acid sulfate soils. At the soil page of the Environmental Literacy Council Web site at http:// www.enviroliteracy.org/subcategory.php/36.html a higher-level overview precedes more external links: follow the internal links on the right side for Soil: Labs and Activities, which includes suggestions for high school curricula. At a greater level of abstraction, information and links from the World of Soil site at http://soil.hostweb.org.uk/ are suitable for high school and college students. With a better informed idea of what soil is and how important soils are to life on Earth, I wanted to see examples of soils and find out whether the differences among soil types were as dramatic as indicated by some of the background Web sites. Links from the USDA’s Natural Resource Conservation Service (NRCS) at http://soils.usda.gov/gallery/ display soil profiles and soil landscapes, as well as interesting soil images with descriptions and their spatial distribution at http:// soils.usda.gov/technical/classification/orders/; find your state soil and learn more about where you are grounded. Visit the photo gallery of A Compendium of Online Soil Survey Information (http://www.itc.nl/~rossiter/research/rsrch_ss_img. html) for links to other soil image sources around the world. The photo gallery at the NRCS, http://photogallery.nrcs.
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Figure 1. The Munsell color chart shown here is used in the field to accurately characterize soil colors, providing information about soil composition and type.
usda.gov, provides access to many images, searchable by U.S. state or category (mostly agricultural), or both. We found this issue’s cover image at this site; you’ll find graphic representations of macro-level soil science concepts here that will build on students’ familiarity with local landscapes. Another soil gallery focuses on arid soils of the Colorado Plateau, specifically the biological soil-crust communities that live at the soil–atmosphere interface, building soils, protecting them from erosion, and conserving soil moisture and nutrients in that environment. See for yourself at http://www.soilcrust.org/ gallery.htm. While the images from the sites just mentioned reveal some of the chemical properties of the soils through color and texture, a Web site from the Thin Section and Micromorphology Laboratory at the University of Stirling, in Scotland, offers a closer look at soil chemistry with microscale soil images. The site’s gallery (http://www.thin.stir.ac.uk/gallery/index.php) includes stunning images of soil thin sections demonstrating the complex interplay of minerals, organic material, bacteria, fungi, plant life, and other soil components. Repeat visits to this site will certainly reward the careful observer and engage student interest. For an extreme close-up view, see the Virtual Museum of Minerals and Molecules displays: try out the Soil Organic Matter site (http://www.soils.wisc.edu/virtual_museum/som/ index.html; Java required), and visualize soil molecules! Hands-On Activities: K–8 At this point I was eager to get my hands dirty, interacting and experimenting with soil. Fortunately, numerous sites provide ideas for activities and laboratory experiments related to soil science, many appropriate to elementary, middle, and high school students, and some suitable for college students, too. Familiar to many K–8 teachers, the Bottle Biology cur-
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Reports from Other Journals
World Wide Web Addresses
Background Information
Photo: Jeff Vanuga, USDA NRCS
riculum includes activities that demonstrate soil formation and the filtering potential of many soil types: the Decomposition Column described at http://www.bottlebiology.org/investigations/decomp_main.html can be adapted for a range of ages and interests by varying the types and amounts of materials added in the bottle. In addition to the activities proposed at the USDA and NASA sites mentioned above, other organizations include soil-related activities for K–8 students. The Field Museum in Chicago has an Underground Adventure exhibit with virtual tour possibilities (http://www.fieldmuseum. org/undergroundadventure/virtual_tour/index.shtml#) and classroom extensions. Under the section Just for Teachers the mud shake activity (http://www.fieldmuseum.org/underground adventure/teachers/mud_shake.shtml) seems feasible and fun. Educators at the Smithsonian Institution are creating a soil exhibit; while it is under construction the staff has been collecting teaching resources on soils (http://www.soils.org/
Figure 2. The woody material in this compostamended soil provides structure and will break down, enriching the soil with carbon.
smithsonian/education.html), including further links to online materials, such as The Great Plant Escape at http://www. urbanext.uiuc.edu/gpe/ with cases for students to solve online in English or Spanish. The Thinkquest site at http://library. thinkquest.org/J003195F/activiti.htm provides detailed instruc-
Resources and Activities for High School Students
http://soils.usda.gov/education/ http://soil.gsfc.nasa.gov/links.htm
http://soil.gsfc.nasa.gov/elec/soilelec.htm
http://www.isric.nl/
http://soil.gsfc.nasa.gov/filter/filter.htm
http://www.enviroliteracy.org/subcategory.php/36.html
http://www.wtamu.edu/~crobinson/SoilWater/capillar.html
http://soil.hostweb.org.uk/
http://www.beloit.edu/~SEPM/Earth_Works/ How_fast_do_sed.html
Soil Galleries
http://www.accessexcellence.org/AE/AEC/AEF/1996/ graham_ecosystem.html
http://soils.usda.gov/gallery/ http://soils.usda.gov/technical/classification/orders/ http://www.itc.nl/~rossiter/research/rsrch_ss_img.html
http://chemistry.org/portal/resources/ ?id=45dc03da647211d7e52c6ed9fe800100 [p 4] http://www.chemistry.org/portal/resources/ACS/ ACSContent/education/curriculum/chemmatters/ tg0403_phytoremediation.pdf
http://photogallery.nrcs.usda.gov http://www.soilcrust.org/gallery.htm http://www.thin.stir.ac.uk/gallery/index.php http://www.soils.wisc.edu/virtual_museum/som/index.html Resources and Activities for Students in Grades K–8
http://www.chemistry.org/portal/a/c/s/1/ feature_tea.html?id=6445e97ac1da11d6f70d6ed9fe800100 Resources and Experiments for Undergraduates
http://www.bottlebiology.org/investigations/ decomp_main.html
http://lawr.ucdavis.edu/classes/ssc102/
http://www.fieldmuseum.org/undergroundadventure/ virtual_tour/index.shtml#
http://www-esd.lbl.gov/CIG/biogeochemistry/jrigce.html
http://links.baruch.sc.edu/faculty/Neubauer/Research.htm
http://www.fieldmuseum.org/undergroundadventure/ teachers/mud_shake.shtml# http://www.soils.org/smithsonian/education.html http://www.urbanext.uiuc.edu/gpe/ http://library.thinkquest.org/J003195F/activiti.htm http://www.wtamu.edu/%7Ecrobinson/DrDirt/filter.html http://www.chemistry.org/portal/a/c/s/1/ wondernetdisplay.html?DOC=wondernet%5Cactivities%5Csoil%5Csoilsizes.html
http://serc.carleton.edu/NAGTWorkshops/geochemistry/ activities/9151.html http://www.rpi.edu/dept/chem-eng/Biotech-Environ/MISC/ phytorem.html http://www.clu-in.org/techfocus/default.focus/sec/ Phytoremediation/cat/Overview/ http://sgs.cnr.colostate.edu/ProgressReports/ 2005_sitereview/booklet/ BGC%20Field%20Tour%20FINAL.pdf http://cbs.umn.edu/cbri/lisa/web/ The access date for all sites is December 2005.
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Photo courtesy U. S. G. S. Canyonlands Research Station
tions for a number of inquiry-based soil activities. Compare the soil filter activity there with this one from “Dr. Dirt”: http://www.wtamu.edu/%7Ecrobinson/DrDirt/filter.html. WonderNet, Your Science Place in CyberSpace, outlines soil science activities as well: http://www.chemistry.org/portal/a/c/s/ 1 / w o n d e r n e t d i s p l a y. h t m l ? D O C = w o n d e r n e t % 5 C activities%5Csoil%5Csoilsizes.html. Resources for High School Students For high school students, more advanced investigations are available. Links from sites already mentioned include activities or experiments suited to high schoolers, including two from the NASA site: Soils As Electrical Systems (http:// soil.gsfc.nasa.gov/elec/soilelec.htm), and Filtering Qualities of Soils (http://soil.gsfc.nasa.gov/filter/filter.htm; and another from Dr. Dirt: Capillary Action (http://www.wtamu.edu/~crobinson/ SoilWater/capillar.html). An experiment, How Fast Do Sediment Grains of Different Sizes Settle?, includes example data from a previous iteration, as well as insightful, challenging questions connecting turbidity, settling rates, and grain size: http://www.beloit.edu/~SEPM/Earth_Works/How_fast_ do_sed.html. The Web site for An Online Project—Comparing Terrestrial Ecosystems in Different States (http://www.access excellence.org/AE/AEC/AEF/1996/graham_ecosystem.html)— outlines a curricular unit on soil science in which students collect local soil samples, test the samples to characterize amounts per volume of nitrogen, phosphorus, and potassium, as well as determining the sample’s pH, water retention capabilities, and whether microorganisms are present. Using the Internet, student teams in different states exchange and compare data, hypothesizing about the land uses associated with soils of other locales. In another example of active student learning, a Chem Matters article (http://chemistry.org/portal/resources/?id=45dc03da647211d7e52c6ed9fe800100, go to page 4) tells the story of high school student Marc Burrell whose intelligence and determination yielded prize-winning chemistry and further data on the effects and limitations of phytoremediation of metal-contaminated soil. Related teaching resources are available at http://www.chemistry.org/portal/resources/ACS/ACSContent/education/curriculum/chemmatters/ tg0403_phytoremediation.pdf. Tales of forensic soil chemistry may also intrigue high school students—check out this site for a brief example: http://www.chemistry.org/portal/a/c/s/1/ feature_tea.html?id=6445e97ac1da11d6f70d6ed9fe800100. Resources for Undergraduates Undergraduate students bring greater knowledge, experience, skills, and questions to scientific inquiry: satisfying soil science resources can be especially rich at this level, although more specialized and compartmented. The study of soil chemistry could take place in a dedicated soil science department, or in departments of geology, agriculture, environment sciences, engineering, biology, or possibly even in the chemistry
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Figure 3. Scanning electron micrograph of cyanobacterial sheath material sticking to sands grains, ⫻ 90. Soil crust-forming cyanobacteria bind soil particles with filaments that exude sticky polysaccharide sheaths, aiding in soil aggregation.
department. During this online journey, myriad college course Web pages on soil chemistry demonstrated that lectures, field studies, and experiments are widely offered under the auspices of many departments. A non-representative sampling includes a useful introduction—Soil Science 102—at http://lawr. ucdavis.edu/classes/ssc102/; results from applied soil chemistry at the University of South Carolina’s Wetland Biogeochemistry Lab concerning tidal freshwater marsh C and N cycling (http://links.baruch.sc.edu/faculty/Neubauer/Research.htm); a lab report on soil respiration and the relative contribution of plant versus microbial respiration from the Biogeochemistry Laboratory of the Center for Isotope Geochemistry, Lawrence Berkeley National Laboratory at (http://www-esd.lbl.gov/CIG/ biogeochemistry/jrigce.html); and a laboratory exercise, Nitrous Oxide Transport and Transformation in Soil, in which students add nitrous oxide to undisturbed soil cores and then experiment with air samples taken from the cores, determining soil properties related to transport of gases: http://serc. carleton.edu/NAGTWorkshops/geochemistry/activities/9151.html. Soil Contamination Soil contamination, whether caused by direct deposition, atmospheric deposition, or through contact with contaminated water, is an urgent problem that soil chemists are particularly situated to address. Phytoremediation, mentioned earlier, uses plants to take up metals from the soil, sequestering the contamination. Student work from the course Web site (Phytoremediation of Soil and Organic Compounds) provides some background: http://www.rpi.edu/dept/chem-eng/BiotechEnviron/MISC/phytorem.html. Find more information (some also in Spanish) at: http://www.clu-in.org/techfocus/default.focus/ sec/Phytoremediation/cat/Overview/. Results and compelling data depictions from student work, presented as a “Final Report”, reinforce the connections among chemistry, soil, and other environmental systems: http://sgs.cnr.colostate.edu/ ProgressReports/2005_sitereview/booklet/BGC%20Field
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Bernadette A. Caldwell is an Assistant Editor, Journal of Chemical Education;
[email protected].
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Photo courtesy U. S. G. S. Canyonlands Research Station
%20Tour%20FINAL.pdf. Explore this topic further at the Atrazine Soil Remediation Field Test remediation pages (http://cbs.umn.edu/cbri/lisa/web/); this could probably be adapted as a case study for use with undergraduate students. In even the few sites discussed, examples of chemical processes relevant to soils abound, including the carbon and nitrogen cycles in soil, acidification of soils through acid deposition (precipitation), leaching in soils, and chemical fates and transport in soil. Soil chemists (or chemists doing soil science) undertake interesting work that yields significant chemical and scientific understandings and applications. The Web sites collected here just scratch the surface of soil science online: consider using these resources as a starting point for your own research of soil topics and curriculum ideas. Dig in!
Figure 4. Photograph of an arid landscape showing an example of healthy, developed soil crusts of the Colorado Plateau, western U.S.
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