National Agricultural Literacy Curriculum Matrix

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Properties of Soils (Grades 3-5)

Grade Level(s)

3 - 5

Estimated Time

Two 45-minute class periods plus short observations

Purpose

Students will learn that different soils have different characteristics and examine different types of soil that have been mixed with water and allowed to settle. Next, they investigate soil components and how air space allows soils to hold and transmit water.

Materials

Activity 1:

3 clear, 12-oz plastic bottles

  • 10 oz each of potting soil, local soil, and sand
  • Water
  • Funnel (optional)

Investigation 1: Collect the following items for every group of 4 students

  • 2 hand lenses
  • 1 teaspoon each of:
    • Potting soil (labeled "Soil A")
    • Local soil (labeled "Soil B")
      • Students can use plastic spoons for measuring soil

Investigation 2: Collect the following items for every group of 4 students

  • 3 clear, plastic cups (9 fluid ounce); approximately 3 inches tall and 3.75 inches across at the top.
  • 1 permanent marker
  • 1/2 cup each of potting soil, local soil, and sand
  • 3 small paper cups each containing 1/2 cup of water
  • 1 ruler

Optional Activity: Collect the following items for every group of 4 students

  • 3 clear plastic cups with holes in the bottom prepared for planting
  • Potting soil
  • Local soil
  • Sand
  • Seeds (choose seeds that germinate fairly quickly, such as peas or radishes)
  • Permanent marker
  • 1 ruler
  • Spray bottle

Essential Files (maps, charts, pictures, or documents)

Vocabulary

inorganic: composed of material from nonliving sources; rocks, sand, and minerals are examples of inorganic materials

organic: living or once-living organisms; derived from living organisms

percolation: the process by which water moves downward through openings in the soil

porosity: the percentage of soil volume that is not occupied by solids

Background Agricultural Connections

After completing this lesson, students will be able to:

  • list aspects of soil composition,
  • recognize that soils vary in composition, and
  • provide examples of ways that soils differ in their ability to absorb water

To prepare for this lesson, teachers should review the preparation instructions for each activity.

This lesson is one of a 5 part series.  See the following titles for related lessons:

  • Plants Around You: Students learn about the function of plant parts and the environment plants need to grow.
  • Properties of Soils: Students learn about the characteristics and components of soil.
  • Plant-Soil Interactions: Students learn about function of roots and how water and nutrients move through the plant.
  • Plant Growth Affects the Soil: Students learn how plant growth takes nutrients from soil and how they can be replaced.
  • How Does Your Garden Grow?: Students make a plan for a garden.

 

Interest Approach – Engagement

  1. Ask students the following introductory questions:
    • Do soils vary in their compositions?
    • Do soils contain materials from both nonliving and living sources?
    • Does soil contain air?
    • Do soils differ in their abilities to hold and transmit water?

Procedures

Activity 1: Properties of Soils

Caution: Be careful when moving the three bottles with the soils settled in water (Step 3). Excessive movement will cause the soil layers to mix together. Try to keep the bottles undisturbed.

  1. Review with students that the nutrients in soil are one of the things that plants need to grow. Ask students, “What is soil?” and “What things are in soils?” Write students’ responses on the board or chart paper.
    • At this time, accept all reasonable answers. Students may suggest that soil is dirt or that it is what plants grow in. When thinking about the components of soil, student responses may include rocks, sand, clay, insects, worms, bacteria, bits of wood and water.
  2. Continue the discussion by asking students, “Can you group the things in soils into different categories?” Ask students what they would put in the different categories. Record their responses on the board or chart paper.
    • Student responses will vary. Guide the discussion to bring out the fact that soil consists of nonliving material, such as clay, silt and sand, as well as living material, such as bacteria, insects, worms, and material from previously living organisms (e.g., dead plant material or even the bodies of decomposed dead animals such as insects). (Materials from living or once living organisms can be called organic, and nonliving materials such as clay, rocks or sand are inorganic materials. Students do not need to learn these terms).
    • Students will observe that the different soils separate differently. At this point, students will not know what is found in each layer. They should record their observations and refer back to them later in the lesson.
  3. Inform the students that they will be making observations of different kinds of soil to learn more about what is in them. Show the class the bottles of potting soil, local soil, and sand that were previously mixed with water and allowed to settle. Explain how they were prepared. Ask students to gather around the bottles and make observations about the different soils.
    Caution students not to pick up or move the bottles.
    • Students will observe that the different soils separate differently. At this point, students will not know what is found in each layer. They should record their observations and refer back to them later in the lesson.
    • The potting soil will show a thick layer of dark material on the bottom, a thick layer of cloudy water, and a thinner layer of material on the top.
    • Local soils may differ, but a typical soil will show layering similar to potting soil, though there may be less material floating on the surface.
    • Most of the sand will form a very thick layer on the bottom of the container. There will be a thick layer of clear water and a very thin layer of material on the surface.
  4. Remind students of the categories that they created earlier (Step 2). Ask students if they can tell which categories match up with the different layers in the bottles.
    • Have students refer back to the lists from Step 2. Student responses will vary. Many students will indicate that things like rocks and sand will sink to the bottom. They may have more difficulty predicting what makes up the upper layers in the bottles. For example, they may be uncertain about what happens to the material from decomposed plants. (Some students may think that dead plant or animal material “ just goes away” so it isn’t in any layer). Listen to their answers to assess what students’ current thoughts and ideas are.
  5. Point out the thin layer that floats on the surface. Inform students that this material is made up mostly of the materials in soil that came from organisms that were alive once but are dead now and have been decomposed by other organisms in the soil.
    • If students are not sure how a once living organism would now be in the soil, you can ask if they have ever seen a tree that has fallen and has started to rot and break down. They may also have seen insects that have died and are in early stages of decomposition.
    • If students have learned about density, you can reinforce their understanding of that concept by explaining that some materials in the soil are more dense (e.g., sand and rock) while other materials are less dense (e.g., clay, the organic material floating on top). However, students do not need to incorporate these terms for this lesson.
  6. Explain to students that the cloudiness in the water comes from small particles called clay. Clay particles are like rock or sand in that they are nonliving. They are very small—so small that they can remain suspended in the water.
    • Students are likely to think that sand particles are small and they sink. They may have trouble understanding that clay particles are even smaller (smaller than they can see as individual particles) and are able to stay suspended in water.
  7. Ask students, “How do soils help plants grow?” Write student responses on the board.
    • Another way to phrase the question is “Why do plants need soil?” Accept reasonable answers at this time—students will continue thinking about the relationship between plants and soil throughout this lesson and continue to deepen their understanding through subsequent lessons. Student responses to the question will vary. Some of the ideas that students may suggest include:
      • Soils provide support for plants’ root systems.
      • Soils provide things that plants need so they can grow.
      • Soils hold water and make it accessible to plants.
    • You may find it helpful to write student responses on chart paper or the board to refer to after students have participated in the investigations.
  8. Ask students, “Do plants grow just as well in any kind of soil?”
    • Students are likely to say that plants grow better in some soils than others, but they may not be able to explain why they think that. Ask students if they can give examples that they have seen that would support their answers.
  9. Inform students they are now going to investigate some other properties of soils that affect plant growth. Divide the class into groups of four students and direct them to their work areas.
    • Student groups will explore two different aspects of soil. Because students will work in groups of 4 for these investigations, you will need to set up multiple lab stations:
      • Investigation 1: Dry Soil
      • Investigation 2: Soil and Air Space
  10. Pass out the appropriate masters to the groups as follows:
    • Investigation 1:
      • Master 2.1, Looking at Soil Samples (2 copies per group)
      • Master 2.2, Investigation 1: Dry Soil (1 copy per student in group)
    • Investigation 2:
      • Master 2.3, Investigation 2: Soil and Air Space (1 copy per student in group)
  11. Instruct students to follow the directions on their handouts, record their observations and answer any questions.  Give students approximately 15 minutes to complete their investigations.
  12. After the groups complete their investigations, reconvene the class and ask each group to take turns describing their investigation and reporting their results.  Student reports will vary. For each type of investigation, summarize the results on the board or an overhead transparency. As necessary, ask guided questions to bring out the following:
    • Investigation 1: Looking at Soil Samples
      • Soils differ in their composition.
      • Soils contain nonliving and living (or once-living) things.
      • Visual inspection cannot fully evaluate everything about soils.
  13. Help students summarize what they have learned in these investigations by asking students to list things that they learned about soils.  Write the list on the board or on chart paper.  Students should mention the following:
    • Soils contain different kinds of materials in them
    • Different soils contain different amount of air spaces between the particles.
    • Different types of soil allow water to pass at different rates.
  14. Explain to students that farmers and gardeners sometimes dig up or till the soil in the spring to loosen it up (make it less compacted) and they may even add decomposed plant and animal materials to the soil. Why do you think they go through these steps to prepare the soil? Can you think of any reason these steps may not be good for the soil?
    • Breaking up or loosening the soil allows air to get into the soil for better root growth, and it may help water penetrate the soil. Adding organic matter to the soil provides plants with things (nutrients) they need. Digging up soil is not always good for plant growth because the soil can wash or blow away more easily, and plants need soil. Many farmers have learned how to grow healthy crops without tilling the soil.

Concept Elaboration and Evaluation

After conducting these activities, review and summarize the following key concepts:

  • There are many different types of soil. Soils can contain different mixtures of particles such as sand, silt, or clay.
  • The composition of soil affects its ability to hold water and nutrients.
  • Different plants prefer different soil types. Farmers manage their soil to meet the needs of the plants they are growing.

Optional Activity: Does Soil Matter?

  1. Explain to students that they are going to investigate the importance of the type of soil for plant growth. In the first lesson, students planted their seeds in potting soil. In this experiment, they will plant seeds in potting soil, local dirt, and sand. Give each team a copy of Master 2.4, Does Soil Matter? (first page). Review the information on the master with students so they understand the investigation they will be doing.
    • Students should write their predictions in the space provided. For example, some students may predict that the seeds will grow better in local soil than they do in sand. Other students may predict that seeds will grow equally well in all three cups. Students will revisit their hypotheses after the seeds have had time to germinate and grow.
  2. Ask students to work in groups of three. Give each group a set of three planting cups. Have students plant 5 seeds, evenly spaced in a cup.
    • Cup 1: Potting Soil
    • Cup 2: Local Soil
    • Cup 3: Sand
    • Make sure students write their names (or otherwise identify) their cups.
  3. Have students check on their seeds every few days. Students can check to see how many seeds germinated in each container and how much the seedlings have grown.
    • Have students record their data and their observations on Master 2.4, Does Soil Matter?  You can give out copies of Master 2.4b as needed. Instruct students where to record their data. You can decide how often students should check their cups. Make sure you water the seedlings frequently. The sand, especially, will dry out fairly quickly. 
    • Note to Teachers: To document the results of the experiment, you could take digital photographs of the growing plants periodically to record the results. The pictures could be stored on your computer. It is helpful to have the seedlings in the three different growing media in the same photograph for comparison or to include a ruler in the photo to help compare sizes.
  4. After allowing the young plants to grow for approximately 2-3 weeks, ask students to summarize what they have observed about their plants.
    • The length of time needed to continue this investigation will depend on a few factors, such as the seeds chosen for the experiment (and how long they need to germinate), the quality of your local soil. If you are in an area that has very rich soil, students may see few if any differences between seedlings grown in local soil and in potting soil. Some differences may take a while to appear. For example, some seeds may sprout equally well in sand and potting soil, but after a period of time, the seedlings in sand may not grow as well as those in potting soil or local soil. Students won’t need to check their plants every day (especially after most seeds have germinated), but they should check them every few days throughout the experiment.
  5. Conclude the activity by asking students to share the results of their investigation.
    • The strategy for how students share their results is your choice. Students can discuss their results or they could create a poster that presents their data. If you choose this option, allow time for students to view the other posters and compare their results to those of other groups.
    • Tip from the field test: Some students were surprised that the seeds in the sand germinated and, at first, seemed to be as healthy as those growing in potting soil or local soil. They observed differences in growth a week or two after germination. The seeds contain nutrients that the young seedling needs, but these nutrients will run out. After that, seeds need to obtain nutrients from the soil.

Essential Links

Suggested Companion Resources

Agricultural Literacy Outcomes

Agriculture and the Environment

  • Explain how the interaction of the sun, soil, water, and weather in plant and animal growth impacts agricultural production (T1.3-5.b)
  • Recognize the natural resources used in agricultural practices to produce food, feed, clothing, landscaping plants, and fuel (e.g., soil, water, air, plants, animals, and minerals) (T1.3-5.e)

Plants and Animals for Food, Fiber & Energy

  • Explain how the availability of soil nutrients affects plant growth and development (T2.3-5.c)

Education Content Standards

Within HISTORY

NCSS 3: People, Places, and Environments

  • Objective 4
    Objective 4
    Factors influencing various community, state, and regional patterns of human settlement, such as the availability of land and water, and places for people to live.
  • Objective 5
    Objective 5
    Physical changes in community, state, and region, such as seasons, climate, and weather, and their effects on plants and animals.

Within SCIENCE

5-LS2 Ecosystems: Interactions, Energy, and Dynamics

  • 5-LS2-1
    5-LS2-1
    Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.

State specific Standards and Objectives

State Standards for UT

Common Core Connections

Speaking and Listening: Anchor Standards

  • CCSS.ELA-LITERACY.CCRA.SL.1
    CCSS.ELA-LITERACY.CCRA.SL.1
    Prepare for and participate effectively in a range of conversations and collaborations with diverse partners, building on others’ ideas and expressing their own clearly and persuasively.
  • CCSS.ELA-LITERACY.CCRA.SL.2
    CCSS.ELA-LITERACY.CCRA.SL.2
    Integrate and evaluate information presented in diverse media and formats, including visually, quantitatively, and orally.

Language: Anchor Standards

  • CCSS.ELA-LITERACY.CCRA.L.1
    CCSS.ELA-LITERACY.CCRA.L.1
    Demonstrate command of the conventions of standard English grammar and usage when writing or speaking.
  • CCSS.ELA-LITERACY.CCRA.L.4
    CCSS.ELA-LITERACY.CCRA.L.4
    Determine or clarify the meaning of unknown and multiple-meaning words and phrases by using context clues, analyzing meaningful word parts, and consulting general and specialized reference materials, as appropriate.

 

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