National Agricultural Literacy Curriculum Matrix
The Rotten Truth
3 - 5
Students will observe and explain the decomposition process and learn the methods and ingredients for making compost.
- 1-quart Ziploc bags, 1 or 2 per student pair
- Masking tape
- Decay Buffet: fruit and vegetable peelings, leaves, small twigs, plastic bag, paper bags, plastic utensils, hay, straw, grass, plastic utensils, paper cups, straws, paper napkins, etc. (Caution: no meat or dairy)
- Soil, 1/2 to 1 cup per student pair
- Spray bottles or bowls of water
- Gloves (food handlers gloves will work)
- Compost Containers handout
- My Compost Pile activity sheet, 1 per student
Essential Files (maps, charts, pictures, or documents)
biodegradable: capable of being broken down by living microorganisms into simpler compounds
compost: decomposed organic matter (plant and animal waste) prepared by people to be used as a soil amendment
decomposer: an organism that digests organic waste and dead organisms by breaking them down into simpler compounds and absorbing soluble nutrients
decomposition: the process of breaking down dead plants, animals, and animal waste into simpler nutrients
nutrient: any element an organism needs to maintain health, grow, and reproduce
soil amendment: a material added to the soil to improve its physical, chemical, and/or biological properties
Background Agricultural Connections
Interest Approach – Engagement
- Introduce the vocabulary words to the students. Assess their prior knowledge by asking a series of questions such as:
- What is compost? Does anyone have a compost pile at home?
- What is a decomposer?
- What does the word biodegradable mean? (Find examples of everyday products at home or around your classroom that are labeled as "biodegradable" or "non biodegradable." Ask students to identify the difference between the two classifications.)
- As a class read the book Magic School Bus Meets the Rot Squad by Joanna Cole. You may also watch the movie.
Activity 1: Decay and Decomposition
- Divide the class into pairs. Give each pair a quart-sized Ziploc. Ask them to write their names on a piece of masking tape and stick it on the bag.
- Set up a “Decay Buffet” of items like those noted in the list of materials.
- Instruct students to place one small piece of each item from the Decay Buffet into their bags. If necessary, have them cut or break the items into small pieces that will fit into the bags. Stress that they not add any meat or dairy to their bags because potentially harmful bacteria could grow.
- Ask one student to place the items in the bag and the other student to record the exact contents. The recorder should also note predictions about what will happen to each item over time. Will the item rot? Smell yucky? Remain the same? You may want to have students switch roles and create a second compost bag with a list of contents and predictions.
- Next, ask students to add about 1/2 cup of soil to their bags and to lightly mist the contents with a plant mister (adding a teaspoon of water and mixing the contents will work the same way).
- Have the students blow into the bags to inflate them slightly and carefully seal them. Once the bags are sealed, leave them for 2–8 weeks. You may decide to keep the bags together or place them in various locations with differing conditions (light, temperature, etc.).
- Note: If students choose their compost bag’s location, ask everyone to register their locations on a master list, or you may be unpleasantly surprised when a missing bag finally makes its presence known.
- Have students create compost bag journals. Ask them to observe their bags periodically and record what they see happening inside. Remind students that they are not to open the bags until the designated date.
- On the designated date, have the students take their bags outside. Distribute plastic gloves to the students to wear while sorting through the contents of their bags with their partners. Caution: Students with known allergies to fungus and fungal spores should not participate.
- Record any items still identifiable and in their present state. Provide spray bottles or water bowls so items can be cleaned off for closer observation and identification. Have students compare their findings to the original list of items and note anything that is missing.
- How did the results compare with the predictions? Did location of the bags make a difference? Define and discuss the process of decomposition.
Activity 2: Containers and Layers for Composting
- Provide each student with a My Compost Pile activity sheet.
- Using the video Dirt, Secrets of the Soil and the Background information, review the methods for making a compost pile.
- Use the Compost Containers handout to discuss different types of containers for composting.
- Optional: Create your own school compost pile.
- Discuss the following questions: Think of some things you’ve thrown away recently. What happens to these things? Do they disappear? Decompose? Remain unchanged?
- What effect do you think light and temperature have on decomposition? Can you think of any other suitable types of compost containers?
Concept Elaboration and Evaluation:
After conducting these activities, review and summarize the following key concepts:
- We rely on soil to grow the food we eat.
- Soil must have nutrients to grow healthy plants. One method of supplying the soil with nutrients is through composting organic matter.
- Compost is decomposed organic matter such as plant and animal waste that can be added to soil for nutrients.
We welcome your feedback! Please take a minute to tell us how to make this lesson better or to give us a few gold stars!
Use the Make Your Own Worm Bin instructions (located in the Essential Files) to create a classroom vermicomposting bin out of a recycled styrofoam cooler. Prepare the cooler ahead of time, and then have students add the bedding, worms, and vegetable scraps. Vermicomposting in your classroom is an effective way to engage students with a wide variety of science concepts. For more information about using the worm bin to investigate ecosystems, life and nutrient cycles, and decomposition, see the lesson Vermicomposting (Grades 3-5).
Suggested Companion Resources
- Make Your Own Worm Bin (Activity)
- A Handful of Dirt (Book)
- Compost by Gosh! (Book)
- Dirt: The Scoop on Soil (Book)
- Soil! Get the Inside Scoop (Book)
- Sophie's Squash (Book)
- Dirt: Secrets in the Soil (DVD) (Multimedia)
- Soil, Not Dirt (Multimedia)
- Learn How To Compost (Website)
- Rocks and Soils (UEN Sci-ber Text for 4th Grade) (Website)
- Soil Center (Website)
Agricultural Literacy Outcomes
Agriculture and the Environment
- 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
- Understand the concept of land stewardship and identify ways farmers care for land, plants, and animals (T2.3-5.e)
Science, Technology, Engineering & Math
- Describe how technology helps farmers/ranchers increase their outputs (crop and livestock yields) with fewer inputs (less water, fertilizer, and land) while using the same amount of space (T4.3-5.b)
Education Content Standards
3-5-ETS1: Engineering Design
3-5-ETS1-1Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.
3-5-ETS1-2Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.
5-LS2: Ecosystems: Interactions, Energy, and Dynamics
5-LS2-1Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.
Common Core Connections
Reading: Anchor Standards
CCSS.ELA-LITERACY.CCRA.R.1Read closely to determine what the text says explicitly and to make logical inferences from it; cite specific textual evidence when writing or speaking to support conclusions drawn from the text.
Speaking and Listening: Anchor Standards
CCSS.ELA-LITERACY.CCRA.SL.1Prepare 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.