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News from Online: Digging Up Earth Day Resourcesby Bernadette A. Caldwell

Soil is both familiar—encountered through child’s playand gardening and cleaning—and mysterious—often invisibleunder crops or grass or pavement, yet capable of nurturing plantand animal life. Intrigued by this year’s focus on soil for Chem-ists Celebrate Earth Day, I went online to see what I couldunearth about soil related to chemistry. While the ensuing jour-ney is not comprehensive, many Web sites cataloged here couldbe profitably used to incorporate soil science and soil chemis-try into your teaching materials for Earth Day and beyond.

General Information

To gain some background understanding, I visited thesoils education home page of the U.S. Department of Agri-culture (USDA) at http://soils.usda.gov/education/, which fea-tures links to many additional internal and external sites.Geared primarily to K–12 students (with the bulk of activi-ties appropriate for K–8 students), the information hereranges broadly from straightforward geology, biology, and soilclassification to more whimsical soil songs and soil poetry.In a similar vein, the soil science education home page atNASA (http://soil.gsfc.nasa.gov/links.htm) provides many use-ful links for teaching soil science to elementary and middleschool students. For a more sophisticated overview, visit theInternational Soil and Reference Information Centre, http://www.isric.nl/ and follow links to About Soils where you’ll findbasic concepts, a glossary, a view of ISRIC’s World Soil Mu-seum (with a virtual tour under construction), and a tutorialand picture gallery on acid sulfate soils. At the soil page ofthe Environmental Literacy Council Web site at http://www.enviroliteracy.org/subcategory.php/36.html a higher-leveloverview precedes more external links: follow the internallinks on the right side for Soil: Labs and Activities, whichincludes suggestions for high school curricula. At a greaterlevel of abstraction, information and links from the Worldof Soil site at http://soil.hostweb.org.uk/ are suitable for highschool and college students.

With a better informed idea of what soil is and how im-portant soils are to life on Earth, I wanted to see examples ofsoils and find out whether the differences among soil typeswere as dramatic as indicated by some of the background Websites. Links from the USDA’s Natural Resource ConservationService (NRCS) at http://soils.usda.gov/gallery/ display soil pro-files and soil landscapes, as well as interesting soil images withdescriptions and their spatial distribution at http://soils.usda.gov/technical/classification/orders/; find your state soiland learn more about where you are grounded. Visit thephoto gallery of A Compendium of Online Soil Survey In-formation (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.

usda.gov, provides access to many images, searchable by U.S.state or category (mostly agricultural), or both. We foundthis issue’s cover image at this site; you’ll find graphic repre-sentations of macro-level soil science concepts here that willbuild on students’ familiarity with local landscapes. Anothersoil gallery focuses on arid soils of the Colorado Plateau, spe-cifically the biological soil-crust communities that live at thesoil–atmosphere interface, building soils, protecting themfrom erosion, and conserving soil moisture and nutrients inthat environment. See for yourself at http://www.soilcrust.org/gallery.htm.

While the images from the sites just mentioned revealsome of the chemical properties of the soils through color andtexture, a Web site from the Thin Section and Micromorphol-ogy Laboratory at the University of Stirling, in Scotland, offersa closer look at soil chemistry with microscale soil images. Thesite’s gallery (http://www.thin.stir.ac.uk/gallery/index.php) in-cludes stunning images of soil thin sections demonstrating thecomplex interplay of minerals, organic material, bacteria, fungi,plant life, and other soil components. Repeat visits to this sitewill certainly reward the careful observer and engage studentinterest. For an extreme close-up view, see the Virtual Museumof Minerals and Molecules displays: try out the Soil OrganicMatter 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, interact-ing and experimenting with soil. Fortunately, numerous sitesprovide ideas for activities and laboratory experiments relatedto soil science, many appropriate to elementary, middle, andhigh school students, and some suitable for college students,too. Familiar to many K–8 teachers, the Bottle Biology cur-

Figure 1. The Munsell color chart shown here is used in the fieldto accurately characterize soil colors, providing information aboutsoil composition and type.

Photo: Lynn Betts, USD

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riculum includes activities that demonstrate soil formationand the filtering potential of many soil types: the Decompo-sition Column described at http://www.bottlebiology.org/inves-tigations/decomp_main.html can be adapted for a range of agesand interests by varying the types and amounts of materialsadded in the bottle. In addition to the activities proposed atthe USDA and NASA sites mentioned above, other organi-zations include soil-related activities for K–8 students. TheField Museum in Chicago has an Underground Adventureexhibit with virtual tour possibilities (http://www.fieldmuseum.org/undergroundadventure/virtual_tour/index.shtml#) and class-room extensions. Under the section Just for Teachers the mudshake activity (http://www.fieldmuseum.org/undergroundadventure/teachers/mud_shake.shtml) seems feasible and fun.Educators at the Smithsonian Institution are creating a soilexhibit; while it is under construction the staff has been col-lecting teaching resources on soils (http://www.soils.org/

smithsonian/education.html), including further links to onlinematerials, such as The Great Plant Escape at http://www.urbanext.uiuc.edu/gpe/ with cases for students to solve onlinein English or Spanish. The Thinkquest site at http://library.thinkquest.org/J003195F/activiti.htm provides detailed instruc-

Background Informationhttp://soils.usda.gov/education/http://soil.gsfc.nasa.gov/links.htmhttp://www.isric.nl/http://www.enviroliteracy.org/subcategory.php/36.htmlhttp://soil.hostweb.org.uk/

Soil Gallerieshttp://soils.usda.gov/gallery/http://soils.usda.gov/technical/classification/orders/http://www.itc.nl/~rossiter/research/rsrch_ss_img.htmlhttp://photogallery.nrcs.usda.govhttp://www.soilcrust.org/gallery.htmhttp://www.thin.stir.ac.uk/gallery/index.phphttp://www.soils.wisc.edu/virtual_museum/som/index.html

Resources and Activities for Students in Grades K–8http://www.bottlebiology.org/investigations/

decomp_main.htmlhttp://www.fieldmuseum.org/undergroundadventure/

virtual_tour/index.shtml#http://www.fieldmuseum.org/undergroundadventure/

teachers/mud_shake.shtml#http://www.soils.org/smithsonian/education.htmlhttp://www.urbanext.uiuc.edu/gpe/http://library.thinkquest.org/J003195F/activiti.htmhttp://www.wtamu.edu/%7Ecrobinson/DrDirt/filter.htmlhttp://www.chemistry.org/portal/a/c/s/1/

wondernetdisplay.html?DOC=wondernet%5Cactivities-%5Csoil%5Csoilsizes.html

Resources and Activities for High SchoolStudents

http://soil.gsfc.nasa.gov/elec/soilelec.htmhttp://soil.gsfc.nasa.gov/filter/filter.htmhttp://www.wtamu.edu/~crobinson/SoilWater/capillar.htmlhttp://www.beloit.edu/~SEPM/Earth_Works/

How_fast_do_sed.htmlhttp://www.accessexcellence.org/AE/AEC/AEF/1996/

graham_ecosystem.htmlhttp://chemistry.org/portal/resources/

?id=45dc03da647211d7e52c6ed9fe800100 [p 4]http://www.chemistry.org/portal/resources/ACS/

ACSContent/education/curriculum/chemmatters/tg0403_phytoremediation.pdf

http://www.chemistry.org/portal/a/c/s/1/feature_tea.html?id=6445e97ac1da11d6f70d6ed9fe800100

Resources and Experiments for Undergraduateshttp://lawr.ucdavis.edu/classes/ssc102/http://links.baruch.sc.edu/faculty/Neubauer/Research.htmhttp://www-esd.lbl.gov/CIG/biogeochemistry/jrigce.htmlhttp://serc.carleton.edu/NAGTWorkshops/geochemistry/

activities/9151.htmlhttp://www.rpi.edu/dept/chem-eng/Biotech-Environ/MISC/

phytorem.htmlhttp://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/

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The access date for all sites is December 2005.

Figure 2. Thewoody materialin this compost-amended soilprovides struc-ture and wil lbreak down, en-riching the soilwith carbon.

Photo: Jeff Vanuga, USD

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tions for a number of inquiry-based soil activities. Comparethe 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 soilscience 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 Cactivities%5Csoil%5Csoilsizes.html.

Resources for High School Students

For high school students, more advanced investigationsare available. Links from sites already mentioned include ac-tivities or experiments suited to high schoolers, including twofrom the NASA site: Soils As Electrical Systems (http://soil.gsfc.nasa.gov/elec/soilelec.htm), and Filtering Qualities ofSoils (http://soil.gsfc.nasa.gov/filter/filter.htm; and another fromDr. Dirt: Capillary Action (http://www.wtamu.edu/~crobinson/SoilWater/capillar.html). An experiment, How Fast Do Sedi-ment Grains of Different Sizes Settle?, includes example datafrom a previous iteration, as well as insightful, challengingquestions 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 Ter-restrial Ecosystems in Different States (http://www.accessexcellence.org/AE/AEC/AEF/1996/graham_ecosystem.html)—outlines a curricular unit on soil science in which studentscollect local soil samples, test the samples to characterizeamounts per volume of nitrogen, phosphorus, and potassium,as well as determining the sample’s pH, water retention capa-bilities, and whether microorganisms are present. Using theInternet, student teams in different states exchange and com-pare data, hypothesizing about the land uses associated withsoils of other locales. In another example of active studentlearning, a Chem Matters article (http://chemistry.org/portal/re-sources/?id=45dc03da647211d7e52c6ed9fe800100, go to page4) tells the story of high school student Marc Burrell whoseintelligence and determination yielded prize-winning chem-istry and further data on the effects and limitations ofphytoremediation of metal-contaminated soil. Related teachingresources are available at http://www.chemistry.org/portal/re-sources/ACS/ACSContent/education/curriculum/chemmatters/tg0403_phytoremediation.pdf. Tales of forensic soil chemistrymay also intrigue high school students—check out this site fora brief example: http://www.chemistry.org/portal/a/c/s/1/feature_tea.html?id=6445e97ac1da11d6f70d6ed9fe800100.

Resources for Undergraduates

Undergraduate students bring greater knowledge, expe-rience, skills, and questions to scientific inquiry: satisfying soilscience resources can be especially rich at this level, althoughmore specialized and compartmented. The study of soil chem-istry could take place in a dedicated soil science department,or in departments of geology, agriculture, environment sci-ences, engineering, biology, or possibly even in the chemistry

department. During this online journey, myriad college courseWeb pages on soil chemistry demonstrated that lectures, fieldstudies, and experiments are widely offered under the auspicesof many departments. A non-representative sampling includesa useful introduction—Soil Science 102—at http://lawr.ucdavis.edu/classes/ssc102/; results from applied soil chemistryat the University of South Carolina’s Wetland Biogeochemis-try Lab concerning tidal freshwater marsh C and N cycling(http://links.baruch.sc.edu/faculty/Neubauer/Research.htm); a labreport on soil respiration and the relative contribution of plantversus microbial respiration from the Biogeochemistry Labo-ratory of the Center for Isotope Geochemistry, Lawrence Ber-keley National Laboratory at (http://www-esd.lbl.gov/CIG/biogeochemistry/jrigce.html); and a laboratory exercise, NitrousOxide Transport and Transformation in Soil, in which stu-dents add nitrous oxide to undisturbed soil cores and thenexperiment with air samples taken from the cores, determin-ing 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 contaminatedwater, is an urgent problem that soil chemists are particularlysituated to address. Phytoremediation, mentioned earlier, usesplants to take up metals from the soil, sequestering the con-tamination. Student work from the course Web site(Phytoremediation of Soil and Organic Compounds) providessome background: http://www.rpi.edu/dept/chem-eng/Biotech-Environ/MISC/phytorem.html. Find more information (somealso in Spanish) at: http://www.clu-in.org/techfocus/default.focus/sec/Phytoremediation/cat/Overview/. Results and compellingdata depictions from student work, presented as a “FinalReport”, reinforce the connections among chemistry, soil, andother environmental systems: http://sgs.cnr.colostate.edu/ProgressReports/2005_sitereview/booklet/BGC%20Field

Figure 3. Scanning electron micrograph of cyanobacterial sheathmaterial sticking to sands grains, � 90. Soil crust-forming cyano-bacteria bind soil particles with filaments that exude sticky polysac-charide sheaths, aiding in soil aggregation.

Photo courtesy U. S. G

. S. Canyonlands Research

Station

Chemical Education Today

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Figure 4. Photograph of an arid landscape showing an example ofhealthy, developed soil crusts of the Colorado Plateau, western U.S.

Photo courtesy U. S. G

. S. Canyonlands Research Station

%20Tour%20FINAL.pdf. Explore this topic further at theAtrazine Soil Remediation Field Test remediation pages(http://cbs.umn.edu/cbri/lisa/web/); this could probably beadapted as a case study for use with undergraduate students.

In even the few sites discussed, examples of chemical pro-cesses relevant to soils abound, including the carbon and ni-trogen cycles in soil, acidification of soils through aciddeposition (precipitation), leaching in soils, and chemical fatesand transport in soil. Soil chemists (or chemists doing soilscience) undertake interesting work that yields significantchemical and scientific understandings and applications. TheWeb sites collected here just scratch the surface of soil sci-ence online: consider using these resources as a starting pointfor your own research of soil topics and curriculum ideas.Dig in!

Bernadette A. Caldwell is an Assistant Editor, Journal ofChemical Education; caldwell@chem.wisc.edu.