MA CURRICULUM FRAMEWORKS

Explain and give examples of the ways in which soil is formed (the weathering of rock by water and wind and from the decomposition of plant and animal remains).

OBJECTIVE

Students will be able to recognize the different elements of the soil food web. Students will understand that soil is alive, and how it is created. Students will understand the importance of building soil and its connections to our own health.

ESSENTIAL QUESTIONS

-Where does soil come from?
-Why is diversity important in an ecosystem?

MATERIALS NEEDED

-Soil Food Web Cards
-Ball of yarn
–Soil Food Web image
-Worm bin for display
-Worms for students to observe

PROCEDURE

Introduction:
Review the different types of soil, from previous activities (Soil in a Jar, Soil Particle Game).
Ask students, “so where does it all begin?” Write their answers on the board. Review an activity from Kindergarten – Living/Nonliving – and ask students to raise their hand if they think soil is alive. Why or why not?
Display the Soil Food Web image (on a screen or as a handout). Discuss the difference between a “food chain” and a “food web”.
Explain the different characters of the food web, with examples of each. Explain what “trophic levels” are, and ask for students to give examples of each trophic level.

Activity:
Part One: Building the Food Web
“Now we are going to recreate the soil food web ourselves, so we can really understand what it takes to make soil.”
Hand out Soil Food Web Cards. Ask students to read their card to themselves and raise their hands if they have any questions about the words on their cards. Bring students into a circle and explain the game.
Ask for a volunteer to start (you could ask for someone who is in the first trophic level).
The first student reads his/her card aloud, and looks around the circle for someone he/she is connected to in the soil food web. He/she tosses the ball of yarn (while holding the end piece tightly) to that person. This continues until each person has received the ball of yarn.
Ask students to look around. Is a web forming? How would this system be different if it were a chain, and not a web? Why is it important to have so many different characters in our soil food web? How would it be different if there were only 5? Discuss the importance of diversity.
Finally, ask students why it is important to create soil?
Part Two: Observing the Soil Food Web
Using the worm bin as an example of the soil food web, and the worms as the largest example of one of our decomposers, students make observations of the decomposition process.
Students observe individual worms (review understanding of worms from 2nd grade unit), their anatomy, and how they are able to break down organic matter to form soil.
Students identify other elements of the soil food web (organic matter, arthropods, etc.)
Ask students to name the elements of the soil food web that they cannot see without a microscope.

Assessment/Wrap-Up:
Students describe the decomposition process in writing. Students create their own soil food web.

FOLLOW UP & EXTENSIONS

-Soil in My Food Web worksheet
-Apple as the Earth activity