Summer Science Teachers Academy

Texas 4-H Center, Brownwood, TX, June 20, 2008

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The Apple as Planet Earth: A quick, simple illustration using an apple to help students understand the importance and limited nature of the soil resource. The earth is shared with about 6.8 billion people, who depend on to produce all the food, fiber and lumber to feed, clothe, and shelter them all, so that the populace does not end up hungry, naked and homeless.
You need an apple and a knife (sharp enough to easily cut the apple). The basic facts you need to complete the demonstration include:
     Approximately 70% of the earth's surface is covered with water (simplify it for cutting an apple to about 75%, three-fourths)
     Half of the part that is not water is in polar ice caps and high mountain ranges (1/2 of 1/4 - note use of math skills, 1/8 remains)
     Of the remaining 1/8, 3/4 of it is too hot, too cold, too steep, too shallow, too wet, too dry, or has some other problem so that it
         cannot be used to produce the food, fiber and lumber to help feed, clothe, and shelter the 6.8 billion people on the planet. This
         leaves 1/4 of 1/8, or 1/32 of the earth's surface that is used in food, fiber and lumber production.
     Actually, though, the soil is only the thin skin (peel a fraction of the remaining slice, so that the peel hangs down), the surface
         1 to 2 meters, which is the part used to produce the food, fiber, and lumber.
     Each year, the population grows, and the soil available for food, fiber, and lumber production decreases due to desertification,
         salinization, sodification, urban sprawl and industrial development, etc. So, farmers around the world have to produce more and
         more food on less and less land every year.
The 1-minute video is found on the American Farmland Trust website (at the bottom). In case the link does not work, the url is: http://www.farmland.org/#.
TEKS:
   Grade 1: 112.3.b1B
   Grade 2: 112.4.b1B, 10B
   Grade 3: 112.5.b1B, 3C, 11A
   Grade 4: 112.6.b1B, 3C
   Grade 5: 112.7.b1B, 3C
   Grade 6: 112.22.b1B, 3C
   Grade 7: 112.23.b1B, 2A
   Grade 8: 112.24.b1B
   Env Sys: 112.44c5A

Scale model of a soil profile: A simple illustration that gives students an opportunity to take home their own microscale model of a real soil profile. It is possible to make this one as complex or simple as you desire. Consider using: Existing road cuts or stream banks on short field trips, 24 to 36" deep hole dug with a shovel in the school yard or lawn, a hole about 2 meters deep x 1 meter wide x 2 or 3 meters long dug by a backhoe, etc.
This activity uses math in developing the scale to represent the depth of the profile.
The direct url is http://soils.usda.gov/education/resources/k_12/lessons/profile/.
    Several other educational activities are included at the parent site: http://soils.usda.gov/education/resources/k_12/. The one above is included in the lessons link.
TEKS:
   Grade 3: 112.5.b3C, 11B
   Grade 4: 112.6.b3C
   Grade 5: 112.7.b3C
   Grade 6: 112.22.b3C, 4 A&B

Soil is a filter: http://www.wtamu.edu/%7Ecrobinson/DrDirt/filter.html
Role of soil in the water cycle: Infiltration, filtration, and storage. Water moves into soil during precipitation events. The rate of water movement is determined by the soil texture and structure (shape of the aggregates, or clumps of soil particles joined together). Coarse soils and well-aggregated soils tend to have higher infiltration rates and better drainage of water through the soil and movement of air
into the soil (aeration). The soil filters pollutants physically, chemically, and biologically as water moves through the soil. If the system is not oveloaded, it functions well. Pollutants reach ground or surface waters when the soil is overloaded with a contaminant.
Water stored in soil can be used by plants, which transpire water back into the atmosphere. Some water stored by soil can be lost from bare soil surfaces by evaporation.
TEKS:
   Grade 1: 112.3.b7A, 10 A-C
   Grade 2: 112.4.b7A, 10 A&B
   Grade 3: 112.5.b2 A-E, 3 A&C, 4 A&B, 7B, 11B
   Grade 4: 112.6.b2 A-E, 3 A&C, 4 A&B, 11A
   Grade 5: 112.7.b2 A-E, 3 A&C, 4 A&B, 6B
   Grade 6: 112.22.b2 A-E, 3 A&C, 4 A&B, 14B
   Grade 7: 112.23.b2 A-E, 3 A&C, 4 A&B (rate of water flow), 8A
   Grade 8: 112.24.b2 A-E, 3 A&C, 4 A&B, 8B, 12C, 14C
   Int Phys Chem: 112.42c2 A-D, 3 A&C, 4B, 9A
   Env Sys: 112.44c2 A-D, 5 B&F
   Chem 112.45c2 A-E
   Phys: 112.47c2 A-F
     (For concepts about water storage, see The Sponge Model: http://www.wtamu.edu/%7Ecrobinson/sponge/index.html.)

Physical model of soil: http://www.wtamu.edu/%7Ecrobinson/DrDirt/soil_air.html
Using the marbles, golf balls, beads, and water in a jar, ask students what they see? Most comment on the marbles, golf balls, and beads. Some will see the water. Say, the marbles, golf balls, and beads remind us that soil always has solid particles in it, and these particles are different sizes. The golf balls represent sand, the largest soil particles. Sand feels gritty when rubbed between the fingers. (Think sandpaper.) The marbles represent silt, the intermediate soil particles. The beads represent clay, the smallest soil particles.
The water is a reminder that soil always has some water in it. Ask what is in the jar that cannot be seen. If the students struggle, prompt them by taking a loud, deep breath. So the model demonstrates that soil always has three phases (solid, liquid, and gas) present at all times. Often, air bubbles can be seen below the water surface, and sometimes water can be seen in menisci above the water surface.
Water stored in soil can be used by plants, which transpire water back into the atmosphere. Some water stored by soil can be lost from bare soil surfaces by evaporation.
TEKS:
   Grade 1: 112.3.b10 A-C
   Grade 3: 112.5.b3C, 7B
   Grade 4: 112.6.b3C, 11A
   Grade 5: 112.7.b3C, 6B
   Grade 6: 112.22.b3C, 14B
   Grade 7: 112.23.b12A
   Grade 8: 112.24.b12C
   Int Phys Chem: 112.42c7E

Soil texture Texture by feel and soil texture triangle: http://www.wtamu.edu/~crobinson/soils/unit_1/txtr_feel.html (sample image at right) Use a bottle or jar to estimate the amount of sand, silt, and clay. This procedure integrates math with science. Measure the constituents of the bottle to estimate percentages by volume occupied. Soil texture is determined from mass fractions. The activity by Ted Sammis also includes densities for an estimate of percentages by mass instead of volume. Background: https://www.soils.org/lessons/plans/lessons/texture.html Activity: https://www.soils.org/lessons/plans/activities/texture.html, Ted Sammis, NMSU TEKS: Grade 1: 112.3.b2B Grade 2: 112.3.b4A, 2B, 4A Grade 3: 112.5.b4 A&B, 11B Grade 4: 112.6.b2 A-E (using different soil types), 4 A&B, 11A Grade 5: 112.7.b2 A-E (using different soil types), 4 A&B, 7B Grade 6: 112.22.b2 A-E (using different soil types), 4 A&B Grade 7: 112.23.b2 A-E (using different soil types), 4 A&B, 8A Grade 8: 112.24.b2 A-E, (using different soil types)3 A&C, 4 A&B Int Phys Chem: 112.42c2 A-D (using different soil types), 3 A&C, 4B, 7E Phys: 112.47c2 A-F (using different soil types)
Add soil to bottle	Add water to bottle	Shake, then measure at 40 seconds	24 hours later

Depth measurements for the bottles shown above. Total soil: 82 mm sand: 40 mm silt: 62 mm clay: 82 mm Determine the relative volume occupied by silt: (silt - sand) = 62 mm - 40 mm = 22 mm clay: (clay - silt) = 82 mm - 62 mm = 20 mm Determine volume percentages of sand: 40/82 * 100 = 49% silt: 22/82 * 100 = 27% clay: 20/82 * 100 = 24% Using this volume estimation, the texture would be sandy clay loam. Using the volume/mass density conversion (Sammis), multiply the percentage of sand by 1.19, the percentage of silt by 0.87 and the percentage of clay by 0.94. Determine the mass: sand: 49% * 1.19 = 58% silt: 27% * 0.87 = 23% clay: 24% * 0.94 = 22% Sammis recommends letting the bottles sit for several days (allows more settling of the particles, especially the clays). This example shows why this is important. The sum of the sand, silt and clay is 103%. It cannot be more than 100%. Taking measurements after a few days should eliminate this problem. The texture from the mass estimates likely will be on the sandy loam/sandy clay loam line.

Making observations
Students are required to make observations, using lenses, microscopes, as well as all five senses. These sand guages are useful to help students observe the difference in size and shape of sand grains. Silt is also shown.
Lenses of 2 to 15x provide better views of the particle shapes, especially for the smaller grains. The illuminated portable microscope shown zooms 60 to 100X. These are useful tools to examine soil particles more closely. These were purchased at Radio Shack, but many other vendors have them, as a web search will reveal.
In the classroom, another possibility is to use a digital USB microscope, or a digital TV microscope, depending upon the technology available to you. These usually zoom to 100 or 200X and may offer the ability to capture images or video.

These sand-guages are available from this supplier.
            W.F. McCollough
            3101 Elkridge Ct
            Beltsville, MD 20705
            301-572-5509
Forestry suppliers has a similar product: sand grain sizing folders.
     http://www.forestry-suppliers.com/product_pages/View_Catalog_Page.asp?mi=3077

Providing the name of a vendor or product does not imply an endorsement of that vendor or product.

TEKS:
   Grade 1: 112.3.b2C, 4A
   Grade 2: 112.4.b2D, 4A
   Grade 3: 112.5.b4A, 11B
   Grade 4: 112.6.b4A
   Grade 5: 112.7.b4A
   Int Phys Chem: 112.42c7E

Observing soil chemical properties
Make a 1:1 vinegar:water mixture. Use a dropper, pipette, or small bottle to apply the mixture to chalk dust, wood (pencil), paper clips, baking soda, and baking powder, and other materials. Observe what happens. The chalk dust, baking soda, and baking powder will fizz (effervesce) with the vinegar mixture. Discuss the chemical reaction with the students. Obtain several different soil samples, including caliche, if available, or soils formed from limestones or marls (most of the Blacklands in Texas). Samples can be obtained from various depths in the soil profile. Have the students predict (hypothesize) what they expect will happen when the vinegar mixture is applied to the soil samples. Then apply the mixture and record the results.
Baking soda is sodium bicarbonate, baking powder has some sodium bicarbonate, but also has calcium and magnesium carbonate and bicarbonates. Chalk is calcium carbonate. These are alkaline materials. The vinegar mixture is acidic. The vinegar (acid) reacts with the carbonates and bicarbonates to release water and carbon dioxide (as a gas - the bubbles observed when efferevescence occurs). Caliche and limestone are calcium and magnesium carbonates and bicarbonates, thus they effervesce when the vinegar mixture is applied. Soils that do not have these compounds in them do not effervesce.
   Grade 6: 112.22.b7 A&B
   Grade 8: 112.24.b9 A&C
   Int Phys Chem: 112.42c7E, 8E
   Chem: 112.45c11C, 14C-D

Nutrients limiting plant growth model demonstration Plants grow in response to the most limiting growth factor. These factors include light, temperature, water, air, and nutrients. The soil provides structure to support the roots, holds and releases water to plants, holds and releases nutrients to plant roots, and recycles nutrients through decomposition of plant and animal residues to form soil organic matter. This is a simple model to demonstrate limiting nutrients. The concept was expressed by Justus von Liebig, a German chemist, using barrel staves to demonstrate that plants grow proportionally to the most limiting nutrient. Prepare a gallon jug by cutting holes in it with a sharp knife, then obtaining rubber stoppers or corks of different sizes to plug the holes. Use a permanent, bold marker to write the nutrients by the corresponding stopper. For more information on plant essential nutrients (those all plants must have to complete their life cycle), see Generalized nutrient cycle and plant essential nutrients: http://www.wtamu.edu/%7Ecrobinson/DrDirt/nutcyc.html For the demonstration, remove the stoppers. Hide the holes and words from the students. Have a water source or another gallon jug of water available, and a pan or tub to catch the leaking water. Ask, "How much water will this jug hold?" When students have answered, pour water from the source into the jug. When water begins to run out the bottom hole, students will usually react. Then turn the jug around and note that the amount of water the jug holds represents plant growht and yield. Discuss the limiting nutrient concept. Start plugging holes from the bottom to show that the jug holds more water, representing more plant growth. Remove one stopper (nitrogen or phosphorus). Show that if all nutrients except that one are present, the growth will not go beyond that hole. TEKS: Grade 1: 112.3.b9A (Might alter slightly to light, air, nutrients, temperature, soil ...) Grade 2: 112.4.b9A (Might alter slightly to light, air, nutrients, temperature, soil ...) Grade 3: 112.5.b3C, 8 A-D (desertification, deforestation, ant dens, termite mounds, etc.), 11B Grade 4: 112.6.b3C Grade 5: 112.7.b3C Grade 6: 112.22.b3C, 14B Grade 7: 112.23.b12B Grade 8: 112.24.b12C Env Sys: 112.44c5F

This is a fun and simple activity related to nutrients. It requires white carnations, food coloring, water, and containers. It can sometimes be continued for a week. The picture below was taken 8 days after the carnations were placed into the dyed water. Nutrient uptake activity using white carnations: http://www.wtamu.edu/%7Ecrobinson/DrDirt/LessonPlan_NutrientMobility.pdf TEKS: Grade 2: 112.4.b7A Grade 3: 112.5.b2 A-E, 3 A&C, 4 A&B Grade 4: 112.6.b2 A-E, 3 A&C, 4 A&B Grade 5: 112.7.b2 A-E, 3 A&C, 4 A&B Grade 6: 112.22.b2 A-E, 3 A&C, 4 A&B Grade 7: 112.23.b2 A-E, 3 A&C, 4 A&B Grade 8: 112.24.b2 A-E, 3 A&C, 4 A&B Int Phys Chem: 112.42c2 A-D, 3 A&C

Living or nonliving: Soil is a system that teems with life. There are more organisms in a handful of soil than there are people on the planet. Contrast soil (living) with a rock (nonliving).
For a closer look at the life in the soil, see these pages by Dr. Thomas Loynachan, Iowa State University.
   Cool soil life videos: http://www.agron.iastate.edu/%7Eloynachan/mov/
   Technique for older students to observe soil life: http://www.agron.iastate.edu/%7Eloynachan/LoynQuickEasy.pdf
TEKS:
   Grade 1: 112.3.b8 A&B
   Grade 2: 112.4.b8 A&B
   Env Sys: 112.44c4 A&B

Renewable or nonrenewable: Correct TEKS answer for soil is "nonrenewable" and for water is "renewable". Not to muddy the waters (pun intended), though, I contend that soil is a "slowly renewable" resources, as depending upon the climate, landscape, parent materials (stuff in which the soil forms), and organisms available (plants and microbes, especially), a soil may form in tens to hundreds of years, though many soils are on landscapes that are thousands of years old (time). I contend that globally, water is a renewable resource. However, regionally, especially in semiarid and arid regions dependent upon fossil water in aquifers that do not recharge, water in those areas is a nonrenewable resource.
TEKS:
   Grade 1: 112.3.b10 A-C
   Grade 3: 112.5.b11A
   Grade 5: 112.7.b11C
   Grade 7: 112.23.b14C (desertification, deforestation, urban sprawl/development, ...)
   Grade 8: 112.24.b14C (desertification, deforestation, urban sprawl/development, ...)
   Env Sys: 112.44c4E (desertification, deforestation, urban sprawl/development, ...), 5C

Dirt Shirts: A brief introduction to soil chemistry and the scientific method that helps students understand and see that differences in soil color are caused by differences in soil properties, especially soil minerals.
TEKS:
   Grade 3: 112.5.b2 A-E, 3 A&C
   Grade 4: 112.6.b2 A-E, 3 A&C
   Grade 5: 112.7.b2 A-E, 3 A&C
   Grade 6: 112.22.b2 A-E, 3 A&C
   Grade 7: 112.23.b2 A-E, 3 A&C
   Grade 8: 112.24.b2 A-E, 3 A&C, 4B
   Int Phys Chem: 112.42c2 A-D, 3 A&C

Contributions of [soil] scientists - http://www.wtamu.edu/%7Ecrobinson/DrDirt/Soil_Science_History.html
Articles are cited that provide the history and contribution of soil scientists to the understanding of soil formation, agricultural production, ...
Six are listed at the beginning as some of the most intriguing: Briggs, King, Whitney, Marbut, Kellogg, and Smith.
TEKS
   Grade 3: 112.5.b3E
   Grade 4: 112.6.b3E
   Grade 5: 112.7.b3E
   Grade 6: 112.22.b3E
   Grade 7: 112.23.b3F
   Int Phys Chem: 112.42c3E (King, Justus von Liebig and Carl Sprengel, tensiometer, Briggs, Hopkins, for a start)
   Chem: 112.45c3E (Justus von Liebig and Carl Sprengel, Hopkins, Milton Whitney, et al.)
   Phys: 112.47c3E (Briggs, tensiometer, et al.)

Other resources and opportunities:
Click on the links above to find the methods for each of the activities above. Visit Dr. Dirt's homepage to find other simple, educational activities suited for you classroom. http://www.wtamu.edu/~crobinson/DrDirt.htm

Smithsonian Soils Exhibit
     http://forces.si.edu/soils/
     Information for teachers: https://www.soils.org/smithsonian/teachers.html

Window on a Wider World: http://www.windowonawiderworld.org/

Panhandle Math-Science Teachers' Conference, September 20, 2008, West Texas A&M University, Canyon, TX
In June, conference information will be accessible from the conference’s website at www.wtamu.edu/pmsc.
If you have any questions, please contact us at 806-651-2906 or acampbell@wtamu.edu .
Dr. Ashley Campbell                                      Mr. Gilbert Antunez
Conference Co-Chair                                     Conference Co-Chair

National Science Teachers' Association: http://www.nsta.org/

Clay Robinson, Ph.D., alias Dr. Dirt
Professor of Soil Science
West Texas A&M University
http://www.wtamu.edu/~crobinson/DrDirt.htm
crobinson@wtamu.edu
office phone: 806.651.2553
fax: 806.651.2938