What's Soil Got to Do With It?

Corroboree 4-H Across the Seas

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OREGON BENCHMARKS

Benchmark 1

Recognize physical differences in Earth materials.

Benchmark 2

Identify properties and uses of Earth materials.

USA NATIONAL SCIENCE EDUCATION CONTENT STANDARDS

Grades K-4

Systems, order, and organization.
Properties of Earth materials.

Systems, order, and organization.

VICTORIAN LEARNING OUTCOMES

Earth and Space Science:

Describe how features of landscapes are altered by the processes of weathering and erosion.

CONTENT OBJECTIVES

Learners will be able to do the following:

Give the names of three sizes of the mineral component of soil.
Explain that soil type is determined by the amount (%)of each mineral component in soil.
Explain how percolation rates differ with soil type.
Name two characteristics of wetland soils.

PROCESS OBJECTIVES

Learners will be able to do the
following:

Make observations.
Ask questions that can be answered through scientific investigation.
Design an investigation to answer a question.
Collect, organize, and summarize data from an investigation.
Analyze and interpret data from an investigation.

What's Soil Got to Do With It?

MATERIALS

What’s Soil Got To Do With It? (PDF - 27KB) one copy/pair of learners

Part 1

Soil samples of sand (purchase sand box grade at a toy store or order from a nursery), a local clay soil, and a sample of a local soil. (If no clay soils are found locally, create your own. Locate a store that carries masonry supplies and purchase clay powder called “ Mason’s Clay” or “Mortar Clay.” Mix in the desired proportions with “regular” soil.)
Six petri dishes
Two squeeze bottles filled with water

Part 2

Soil samples of sand, a clay soil, and a local soil.
Soil Tube Assembly: Set of three tubes each, labeled “sand,” “local,” “clay.” Download instructions for constructing the Soil Tube Assembly (PDF - 31KB)
Two measuring cups, 250 ml polypropylene beakers
Six small collection cups, 50 ml polypropylene beakers

Part 3

One set of Soil Texture Cue Cards (PDF - 18KB). Copy the Activity Card Masters from Appendix III onto card stock: SAND; SILT; CLAY; SANDY CLAY LOAM = 55% SAND (16/30) + 20% SILT (6/30) + 25% CLAY (8/30)

PREPARATION

For this lesson you’ll need to collect three soil samples. If possible, obtain a sample of sand and clay. The third soil can be a local backyard soil from any learner’s home.

Sand box sand can be obtained from toy stores or nurseries. It can be used “as is” or mixed with a garden soil. To determine if a local soil is a clay, you’ll need to perform a test similar to the one the learners will be doing. Refer to the county Soil Survey book for help in locating soil types, or ask for help from your Extension Service or Natural Resources Conservation Service professionals.

To test for texture, slightly wet a small sample of soil in the palm of your hand. Feel the soil. The clay soil will not feel gritty. Clay will mould into a sticky ball and can be rolled into a long thin rod
and bent into a ring without breaking. Silty soils feel smooth, like flour. They are neither gritty nor sticky. A loamy soil is intermediate between sand, silt, and clay. It will feel a little gritty and can be molded into a ball without feeling very sticky at all.

Collect the sand, clay, and local soil. Measure out a small amount of sand onto two dishes. Repeat for clay and the general soil. You should have two dishes each of sand, clay, and local soil. Have ready the two Soil Tube Assembly stands and six clear tubes. Check the condition of the Soil Tube Assembly and tighten the metal holding clamps around the clear tubes by using a screwdriver on the nut. The cheese cloth filters at the base of each tube should be held tightly in place by the black rings. For each set of three tubes, one should be labeled Sand, one should be labeled Clay, and one should be labeled Local. Fill each tube in turn as labeled with one of the three soil samples. Each tube should be filled to within 3 inches of the top opening.

PROCEDURE

Part 1

Texture by Feel Test

Divide the learners into two groups and pass out one copy of the What’s Soil Got To Do With It? worksheet to each group. Have available the water squeeze bottles and the set of dishes of dry sand, clay, and local soil to each group. Demonstrate how to feel soil texture. Ask learners to fill in the chart and answer the questions under Part 1—Texture by Feel.

Part 2

Percolation Test

Have available the Soil Tube Assembly, one measuring cup per group, and the collection cups. Have learners place the collection cups under the soil tubes. Read the learners the directions for the experiment and data collection on Part 2 of the worksheet. Ask learners to complete Part 2 of the worksheet. Caution learners to keep an eye on the collection cup as they add water to their soil tubes, so as not to overflow the cups and flood the table.

Ask learners:

How did the learners’ prediction of percolation rate on the worksheet at (3) compare to their observations at (6)?
Did water stand on the top of any soil types?
How could learners tell that a soil had become saturated?
Did water flow out of any soil at the same rate it was poured onto it?

Part 3

Creating a Flower Pot

You may wish to hold this activity and have students view the videotape prior to presenting parts 1 and 2. This activity can be done in any open area making use of natural boundaries or painted lines on the playground. The leader might wish to use sidewalk chalk to draw a flower pot outline big enough for the group to stand in.

Take the learners and the Soil Texture Cue Cards outside. Ask the learners to stand in the flower pot. Have one learner step out of the flower pot to act as “Rosa Raindrop.” The other learners will begin by becoming sand particles. Post the Cue Card for sand where everyone can see it. To "become” sand, each learner should stand with their arms outstretch and their hands clenched. They should stand so that they can turn around (gently!) and just touch their neighbor’s knuckles.

When all the learner sand particles are in position, ask them to freeze. Then ask Rosa Raindrop to begin at the top of the flower pot, infiltrate the soil, percolate down through the sand, and out the bottom of the flower pot. How hard was it for Rosa Raindrop to infiltrate and percolate through sand?

Repeat this exercise with the learners becoming silt. Post the Cue Card for silt where everyone can see it. To become silt particles each learners will stand with their hands on their hips and their elbows extended. They should stand so that they can turn around and just touch their neighbor’s elbow. How much of the pot do they occupy? Ask Rosa Raindrop to percolate down through the silt. How hard was it for Rosa Raindrop to percolate through the silt? How does silt compare to sand for ease of water percolation?

Repeat this exercise with the learners becoming clay. Post the Cue Card for clay. To become clay particles, each learner will stand with their arms at their sides and their shoulders touching the next person. How much of the pot do they occupy? Ask Rosa Raindrop to percolate down through the clay. How hard is it for Rosa Raindrop to percolate through clay? How does clay compare to sand and silt for ease of percolation?

If time allows, create a sandy clay loam soil in the flower pot. Post the Cue Card for Sandy Clay Loam. A sandy clay loam is made of 25% clay, 20% silt, and 55% sand. With 10 learners, a sandy clay loam would be 3 clay learners (arms at sides), 2 silt learners (hands on hips), and 5 sand learners (arms outstretched). Assign the number of learners needed to create the correct number of each soil particle size. Mix the learners up into a Sandy Clay Loam. Ask Rosa Raindrop to infiltrate and percolate once again. Compare Rosa’s progress to the previous soil types.

Which soil do learners believe is the most permeable? Which would learners expect to have the fastest percolation rate? Which of these soils would learners expect to find in a wetland? After the discussion, return the learners to the classroom.

Cleanup

Be sure to clean out the Soil Tube Assembly tubes thoroughly immediately after the lesson to avoid the soil materials solidifying and causing damage to the tubes when cleaned.