Investigating Properties of Soils

Synopsis***************
PLAN - Properties of Soils: Loam, Sand, Clay

DO
1. Review erosion and weathering facts.
2. "A Closer Look at Soils" lab
3. Gather as a class and discuss results

STUDY - Describe properties of loam, sand, and clay

ACT - Review properties w/class

Detailed***************
PLAN
Performance Indicators:
1) Students will compare a mystery sample of soil with a given sample. They will be asked to observe and describe their mystery sample and compare its properties with the given sample.
2) Classify an assortment of pictures depicting various natural resources as renewable, nonrenewable, or inexhaustible. Summarize the importance of these materials by providing at least one example of how each is used in the local area (

Key Understandings and Guiding Questions:
1) Rocks, soil, water, and air represent natural resources.— Which resource is the most important: rock, soil, water, or air?
2) All natural resources are renewable, nonrenewable, or inexhaustible.
— What is a natural resource?
— Why is it important to protect this natural resource?
3) The properties of matter (soil) determine their possible uses.— What are some properties of soil?
— How do soils differ?
— How do the different properties of soil make it useful?

Vocabulary of Instruction:
weathering
soil
properties
texture
retain

Materials:
studentjournals
cookies
chart and markers or board
paper plates
small plastic jars or containers with lids
water
paper towels
loam
measuring spoons
plastic spoons
sand
clay
crayons
hand lenses
water misters
measuring cups
sticky notes
two liter or three liter bottles
rubber bands
coffee filters
graduated cylinders
sponges
scissors
water droppers

Resources:
The following links provide photos of landslides, weathered rock formations, and river worn rocks.
http://landslides.usgs.gov/learning/photos/catalina_mountains__arizona_2006_event__u.s._/sabino_canyon
http://3dparks.wr.usgs.gov/joshuatree/html/a59.htm
http://3dparks.wr.usgs.gov/mtrainier/html2/mr916.htm
http://www.epa.gov/safewater/kids/grades_k-3_groundwater_movement.htmlis a website for a lesson on permeability and porosity.
http://www.globe.gov/fsl/html/templ.cgi?EG_soil&;lang=en&nav=0is a website that will allow teachers to download a soil module storybook.

DO
Instructional Procedures
1. Distribute the following to each student or student group: cookies (some kind that has pieces of nuts, etc.), paper plates, and small plastic jars or containers of water.
2. Explain to the students that the cookie, once again, represents a slab of rocky earth material. Provide the following directions:
Drop the cookie onto the paper plate from chin level.
Ask: What happened to the rock, chalk or cookie? It broke into pieces of various sizes.
Pick up the plate of pieces. Rub two of the pieces together over the paper plate.
Ask: What did you see happening? The pieces are grinding down into smaller pieces. What happened to the original pieces? They got smaller and were shaped differently.
Say: Place all of the pieces into the plastic jar/container (teacher fills it 2/3 full of water). Put the lid on securely and shake the container to allow the water to wash over the pieces.
After a few minutes, ask: What did you observe in the jar? The cookie has worn down even more. The water is cloudy or murky and not clear. Smaller pieces may have broken off and settled to the bottom or be floating on top.
3. Show students pictures of:
1) a landslide or avalanche,
2) a weathered rock formation, and
3) a rushing stream with smooth river rocks.
Tell students that the rocks in the pictures have been broken and worn down into smaller and smaller pieces by several forces: gravity, wind, and water.
Ask (as you show each picture): What force might have caused the rocks to fall down the cliff or mountainside and break into smaller pieces? Gravity
How did we model this with our cookie? We dropped it and it broke. What force might have carved out this shape by wearing it down with blowing sand? Wind
How did we model this with our cookie? We rubbed them together wearing them down into smaller pieces and reshaping them.
What force might have tumbled these rocks until the edges were broken down and smooth? rushing water
How did we model this with our cookie? We tumbled them in water breaking them down further into smaller and smaller pieces.
4. Explain to students that forces such as wind, water, and gravity break rock down into smaller and smaller pieces. Humans do this as well. Remind students about how they broke the cookie (rocks) while mining for chocolate chips (coal deposits). Tell students that this process of breaking rocks down into smaller and smaller pieces is called weathering. Over millions of years, weathering (caused by forces such as wind, water, and gravity) has changed the Earth’s surface.
5. Have students examine the various sized particles from the cookie model. Explain that as the Earth’s rock materials are broken down into smaller and smaller pieces, those pieces are given different names. Very large rocks are sometimes called boulders. Smaller pieces may be called rocks. Rocks then become pebbles, pebbles become gravel, and gravel is worn down into even smaller particles called sand, silt, and clay. These smaller particles (known as sand, silt, and clay) become part of another very important natural resource, the Earth’s soil.
6. Dispose of cookie material and clean up the area.

STUDY
1. Distribute bags of rich topsoil called loam (or potting soil), spoons, paper plates, and hand lenses to each group of students. Instruct them to use their senses to observe the soil. Each student can put a spoonful of the soil on their plate to examine and manipulate (this is a hands-on activity). Challenge them to come up with several different observations using each sense (except taste).
2. Have students share some of their observations as a class. If students haven’t provided general information about color, consistency, texture, odor, or sound when rubbed on the plate, prompt them to examine those properties more closely.
Ask:
Did you have any surprises? Students should notice that there are other things in the soil besides particles of rock such as remains of plants and/or animals. Why might there be remains or parts of plants in the soil? Answers may vary
What animals might be living in the soil? Answers may vary
What would happen if there weren’t any soil? Accept all answers.
3. Remind students about the earlier activity in which you planted bean seeds in 4 different earth materials. Refer to the bar graph with the students‟ predictions.
Ask: What must the soil provide for plants to be able to grow and function? Students should indicate that plants need water, food, air, sunlight, and space. Do you think any of these 4 earth materials is too rocky to support the growth of plants? Students should indicate or reiterate that the gravel is too rocky. Do you they think that all soil is the same? Answers may vary
4. Let’s look at some different soils: loam (potting soil), sand, and clay.
5. Distribute bags of sand and clay, and two more paper plates, to each group of students. Students should still have spoons and hand lenses from their previous work with loam (potting soil). Each student can put a spoonful of the sand and clay onto two separate plates to examine, manipulate, and compare. Challenge them to come up with several different observations using each sense (except taste).
6. Allow students time to observe the physical properties of their samples and record their findings (including their observations from the previous loam exploration) in a three-column T-chart in their journal. The handout: Properties of Soil can be used as a guide.
7. After students have explored and recorded their observations, ask: Do the samples look the same? Answers may vary, but samples should appear different. What other tools or activities could you use to study the soils more closely? Answers may vary, but students might suggest using microscopes or hand-held microscopes, adding water, performing other fair tests, etc.
8. Distribute the handout: A Closer Look at Soils to the students.
Say: Using tools of science including our senses, a hand lens (or microscope), a water mister, and this handout, we are going to further explore the three samples. Observe the color of the samples of soil and indicate your observation in the first row of the table. Using your hand lens, look closely at the different soils. Record your observations. After rubbing the soils between your thumb and index finger, record what you feel. Tell students that after observing the soil while it is dry, they can add water to learn more about its texture, color, shape and flexibility, etc. Mist your samples with the water mister. How do the samples behave? Put the moist samples in your hand. Roll the moist samples with your fingers. Record your findings in the chart. Last of all, using your sense of smell, waft or wave the air above the moist samples toward your nose. If a scent is detected, record that information or data into the chart as well.
9. Allow students to share their findings with the class.
10. While students still have the bagged soil samples and moistened spoonfuls of different soils, share with students the first 4 directions for the next activity from the handout: It’s Settled. It is not necessary to distribute the handout at this time.
11. Provide the containers, water, and measurement tools as listed on the handout: It’s Settled.
12. Student groups should place their “settling” containers in an area that will remain undisturbed until the next day. This would be a good time to conclude the day’s activities since the results of this test will not be observable right away.

ACT
Using their experiences from the past few days, students are going to explore a “mystery” soil sample. Students are expected to use their notes from previous soil observations and tests to help them identify the properties of this “mystery” soil. Students need to record their observations on the handout.