Is Soil Alive?

Key Topics/Vocabulary: Soil Composition, Soil Formation, Soil Food Web, Decomposition, Weathering, Nutrients, Humus, Top Soil, Sand, Clay, Silt, Loam

Grade Level: 3rd-6th

Series #1 Description

Spanish Lesson Plan

Science Framework

Lesson Video

Lesson Bridge:

Begin this series by emphasizing that soil is the foundation of all life. Because of this, we need to ensure that our soil is healthy so that our plants can grow big and strong!

Lesson Overview:

In this lesson, students will learn that soil is home to billions of organisms that play vital roles in decomposition and ecosystem health. Students will use their senses to discover the qualities of different soil types and understand what these qualities provide for plants in terms of food, water, and shelter. They will then practice setting up an experiment to test which mixture of soils helps support plant growth best!

Learning Objectives by Grade Level:

• 3rd Grade: 3-LS4-3 Construct an argument with evidence that in a particular habitat some organisms can survive well, some survive less well, and some cannot survive at all. (How do different soil types affect plant growth?)
• 4 Grade: 4-LS1-1 How does soil affect root and plant growth?
• 5 Grade: 5-ESS2-1 How does water interact with soil?  How do life forms in the soil interact with the soil to change it?

Essential Question(s) that Connect CCCs and SEPs:

• How is clay different from silt or sand? Which one has the smallest particles? Which one has the biggest particles? (Scale, Proportion, & Quantity; Analyzing and Interpreting Data)
• How does soil affect plants and animals? Does healthy soil cause healthy animals and plants? (Cause & Effect; Asking Questions & Defining Problems).

Vocabulary:

Soil Composition- The mixture of minerals, water, air, organic matter, and microorganisms that makeup soil

Humus (Hue-muss) - A dark and rich part of the earth formed by decaying organic matter

Sand- Mixture of very small pieces of rocks and minerals (large particle size)

Clay- Mixture of tiny tiny particles or pieces of minerals

Silt - Small particles or pieces left as sediment from water

Loam- A blend of sand, silt, and clay that is ideal for plant growth

Materials:

• 4+  tubs with different types of soil (sand, clay, silt, humus/organic matter).
• Labels for the soil samples
• 1 large, clear jar per session. (this can be a large mason jar, gallon water jug with the top cut off, clear bucket, etc.)
• Biodegradable Tape
• Trowels
• 5 gallon bucket
• Garden Journals (optional)
• Soil Organism ID Chart (optional)
• Microorganisms examples
• Exit ticket (optional)

Prep:

Find good examples of clay, silt, sand and humus/organic matter to bring to the school for demonstration (or, identify which soil types are already existing in your garden). River banks and beaches are good places to find sand. Silt can be found in creek beds. Look for clay from the soil gophers bring up from their holes, or the edges of lakes/ponds.

Activity Procedure:

Engage:  

Hold up a tablespoon of garden soil and ask students to guess how much bacteria is in it (answer billion!)

Think, Pair, Share: How much bacteria do you think is in this spoonful of garden soil?

Sentence frame: I estimate that there is ______ bacteria in that spoonful of garden soil.

Explain that bacteria is a kind of germ that lives all around us and is too small to see. Some kinds of bacteria make us sick but some are crucial in helping our plants grow!

Explore:

Gather students into groups and direct them to the different tubs of soil and observe using their eyes, hands, ears, and noses (not tongues!) If you choose,  you can also have the same soils in wet and dry form so the kids can experience the differences … but be prepared for a mess!

Once they’ve gone through all the stations, have them return to your stump circle/teaching area.

Explain:

Many of the characteristics of these soils are explained by particle size and shape. Draw each soil particle on the board for students to observe. Clay: small and flat; Silt: slightly larger than clay but still flat; Sand: medium and sharp/jagged; Humus: large or small and spongy. 

Soil particles are created by a process called weathering. Explain how the process of weathering creates soil.

Think, Pair, Share: Which of the soils would you plant a seed in? Why?

Sentence frame: I would plant a seed in _______ because __________

Could one of the soils drown your plant? Which soil would be bad during a drought? Which soil is richest in nutrients?  Based on soil particle structure, which soil is the best for stabilizing a plant? As you can see, each of these soil types have properties that are positive and negative for plants.  For example, humus is a rich nutrient source (look at the color!) but it is so loose that it can erode very easily and not provide the best shelter for a plant.

Thumbs up/down: Do you think there is hummus in the soil in the garden?

 What type of soil do you think we would prefer to have in our garden? (A mixture of all the different soil types). This is called a loam.

Action: Testing Soil in a Jar

1. Review your Garden Agreements
2. Give each student a trowel and have them each take a soil sample from the garden. *If you do not have enough trowels for everyone, break students into groups and have them take turns. Or, complete this step as one group and ask for volunteers to take the samples.
3. Add all samples to the bucket.
4. Take turns mixing the soil samples to make one homogenous mixture.
5. Fill your jar ⅓ full of soil and the rest of the way with water.
6. Shake the jar! Pass the jar around the class while asking students what their predictions are. Let students take turns shaking.
7. Label the jar with the classroom # or the teacher's name and date.
8. Let sit. Explain that with time, the different soil types will form different layers in the jar because of the other particle sizes. Revisit your pot during the next lesson in the series to identify your soil layers. (Clay should be the lightest and on top, then silt sand will be on the bottom)

Reflect:

What did you notice about the soil you collected in the garden? Was it hard or soft? Judging by what you saw and comparing it to the soils in the tubs, which type of soil do you think your sample was? How do you think the soil in our garden was made? What lives inside the soil that we can’t see? (Bacteria). What animals help make soil? (Decomposers). If there’s time, have students complete the exit ticket and turn them in on their way out.

Extension Activities:

• Do a decomposer hunt. Looking for what crawlies live in the soil.
• Ask students to do research on decomposers, pick their favorite decomposer, and then write and draw a cartoon strip of them hard at work in the compost pile.  For inspiration, read The Diary of a Worm by Doreen Cronin.
• Watch our virtual lesson video as a preview or review

This lesson was prepared by One Cool Earth under an award

NA20NOS4290033 from the Bay Watershed Education and Training Program

of the National Oceanic and Atmospheric Administration (NOAA), U.S.

Department of Commerce. The statements, findings, conclusions, and

recommendations are those of the author(s) and do not necessarily reflect

the views of NOAA or the U.S. Department of Commerce.