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Lesson: Composting – Nature's Disappearing Act

Quick Look

Grade Level: 3 (3-5)

Time Required: 1 hours 30 minutes

(Spread across 5 days. See the Procedure section for timing details.)

Lesson Dependency: None

Subject Areas: Science and Technology

Summary

Students explore the concept of biodegradability by building and observing model landfills to test the decomposition of samples of everyday garbage items. They collect and record experiment observations over five days, seeing for themselves what happens to trash when it is thrown "away" in a landfill environment. This shows them the difference between biodegradable and non-biodegradable and serves to introduce them to the idea of composting. Students also learn about the role of engineering in solid waste management.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

A photograph shows a pile of trash — cans and scraps of metal — that are in various stages of breakdown.
Students explore biodegradability.
copyright
Copyright © Microsoft Corporation 1983-2001

Engineering Connection

Engineers are challenged with the problem of quickly and efficiently composting landfills, turning food, yard and animal waste into high-nutrient soil. By designing landfills to decompose garbage quickly (5 to 10 years), engineers create environmentally friendly ways to eliminate trash and generate landfill gas to produce electricity.

Learning Objectives

After this activity, students should be able to:

  • Define biodegradable and non-biodegradable.
  • Explain how engineers work to reduce solid waste.
  • Gather and record data and observations based on a landfill experiment.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS Performance Expectation

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

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This lesson focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Develop a model to describe phenomena.

Alignment agreement:

Science explanations describe the mechanisms for natural events.

Alignment agreement:

Use a model to test interactions concerning the functioning of a natural system.

Alignment agreement:

The food of almost any kind of animal can be traced back to plants. Organisms are related in food webs in which some animals eat plants for food and other animals eat the animals that eat plants. Some organisms, such as fungi and bacteria, break down dead organisms (both plants or plants parts and animals) and therefore operate as "decomposers." Decomposition eventually restores (recycles) some materials back to the soil. Organisms can survive only in environments in which their particular needs are met. A healthy ecosystem is one in which multiple species of different types are each able to meet their needs in a relatively stable web of life. Newly introduced species can damage the balance of an ecosystem.

Alignment agreement:

Matter cycles between the air and soil and among plants, animals, and microbes as these organisms live and die. Organisms obtain gases, and water, from the environment, and release waste matter (gas, liquid, or solid) back into the environment.

Alignment agreement:

A system can be described in terms of its components and their interactions.

Alignment agreement:

NGSS Performance Expectation

5-ESS3-1. Obtain and combine information about ways individual communities use science ideas to protect the Earth's resources and environment. (Grade 5)

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This lesson focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Use evidence (e.g., measurements, observations, patterns) to construct an explanation.

Alignment agreement:

Make observations and/or measurements to produce data to serve as the basis for evidence for an explanation of a phenomenon.

Alignment agreement:

Human activities in agriculture, industry, and everyday life have had major effects on the land, vegetation, streams, ocean, air, and even outer space. But individuals and communities are doing things to help protect Earth's resources and environments.

Alignment agreement:

A system can be described in terms of its components and their interactions.

Alignment agreement:

  • Waste must be appropriately recycled or disposed of to prevent unnecessary harm to the environment. (Grades 3 - 5) More Details

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  • Models are used to communicate and test design ideas and processes. (Grades 3 - 5) More Details

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  • Investigate and identify two or more ways that Earth's materials can be broken down and/or combined in different ways such as minerals into rocks, rock cycle, formation of soil, and sand (Grade 3) More Details

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  • Use evidence to develop a scientific explanation about one or more processes that break down and/or combine Earth materials (Grade 3) More Details

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Worksheets and Attachments

Visit [www.teachengineering.org/lessons/view/cub_environ_lesson05_activity2] to print or download.

Introduction/Motivation

What do we mean when we say something is "environmentally friendly" or "environmentally unfriendly"? (See what students think.) We are deciding whether or not it causes more harm to the environment than good. More specifically, we classify waste in the environment as biodegradable or non-biodegradable. Biodegradable items are usually considered "environmentally friendly."

What do we mean when we say that something is biodegradable? (Listen to student ideas.) We mean that it is a substance that can be broken down by natural environmental processes into basic elements such as carbon dioxide, nitrogen and water. This may seem simple, however, nature only breaks down things that nature creates. For example, nature does not make plastic and is unable to easily break plastic down into its basic components. If nature cannot break something down into basic elements, then we label it as non-biodegradable. Plastic is considered non-biodegradable. Sometimes, biodegradable items do not break because they are deprived of environmental conditions or (to help you remember), LAWS: light, air, water and soil.

Much of the waste in our landfills is biodegradable. However, many of our current landfills do not permit naturally biodegradable things to decompose because they are deprived of light, oxygen and often moisture. Sometimes this is done on purpose to prevent gas production in landfills, but it means the biodegradable trash never goes away (does not decompose).

Composting is a way to decompose food, yard and animal wastes into new soil. Some engineers are specialists in optimizing the process so that biodegradation takes place more quickly and efficiently. This means that the engineers devise ways to make composting and landfills work better. This helps us manage the garbage and waste in a way that is less harmful on the environment and is more environmentally friendly. One idea is to do composting in your own yard with your own kitchen and yard waste. Composting reduces the amount of trash that you send to a landfill and creates a rich soil amendment to add back to your yard to benefit the plants and landscaping. The Seattle Zoo in Washington composts elephant manure and gives it away free to gardeners as "Zoo Doo."

Who knows what a "model" is? (Listen to student ideas.) One type of model is what engineers do when they want to really understand something and make it better, and they don't want to make it full scale for testing. Today we are going to make our own model landfills and look at how composting works in a model environment.

Vocabulary/Definitions

biodegradable: Substances that can be broken down by natural environmental processes (involving microorganisms) into basic elements such as carbon dioxide, nitrogen and water.

composting: A process in which food, plant, yard and animal waste decomposes into new soil. Engineers often work to optimize the process so that biodegradation takes place more quickly and efficiently.

decompose: To break down into basic elements. Often called "rotting."

decomposer: The bacteria, fungi, earthworms, etc. that eat the remains of dead plants and animals and release basic elements (like nitrogen) back into the environment.

model: (noun) A representation of something for imitation, comparison or analysis, sometimes on a different scale. (verb) To make something to help learn about something else that cannot be directly observed or experimented upon.

nitrogen cycle: A natural process that recycles nitrogen back into the environment. Plants absorb nitrogen compounds from the soil; animals eat the plants, passing the nitrogen along the food chain; when animals and plants die they decompose, with the help of decomposers, and the nitrogen compounds again become part of the soil. (Note: The sulfur and phosphorus cycles are similar.)

organic: That which is created from living organisms.

Assessment

Pre-Activity Assessment

Discussion Questions: Lead a class discussion to assess students' base understanding of the activity topics. Ask the students:

  • What do we mean by "biodegradable" and "non-biodegradable" items? What are some examples of each?
  • What are some things that are required in order for items to biodegrade? (Answer: Light, moisture, oxygen/air.)
  • Why is biodegradation an important part of nature? (Answers: It helps get rid of waste in the environment. It keeps the nitrogen cycle and thus, the circle-of-life going. It recycles what might be consider unwanted materials into valuable resources.)
  • Why is biodegradation an important idea related to solid waste management? (Answer: Much of the material in our landfills is biodegradable, such as food, plant and yard waste, but in many current landfills these biodegradable items never decompose because they have no access to light, oxygen and moisture. This is done to prevent leaching and methane production in landfills.)

Activity Embedded Assessment

Diagramming: Ask students to draw a descriptive diagram of their landfill models in the space provided on the worksheet. Remind them to label each of the garbage test samples.

Predictions: Ask students to write down their predictions on the worksheet, indicating which test items in the model landfill they expect to break down first and last. Have them explain their reasoning.

Observations: Have students record their observations as prompted by their worksheets.

Post-Activity Assessment

Worksheets: Have students complete the last four questions on their worksheets. Review their answers to assess their depth of comprehension of the activity concepts.

Sales Pitch: Working together as if they are engineering teams, have student groups come up with a sales pitch for a product to dispose of biodegradable or non-biodegradable waste. Have them brainstorm the product, prepare the sales pitch, and present to the rest of the class. Their presentations reveal their understanding of the activity content.

Lesson Extension Activities

Have each group suggest and test additional, different items as garbage samples.

Continue the activity longer than five days to see if some of the items eventually biodegrade with more time. Have students graph their data on the different items and degradation time. What patterns are revealed in the graphs?

Have students layer their landfills: soil, garbage, soil, garbage, etc. Have them compact it tightly. Doing this is a more accurate model of of a real-world sanitary landfill. By comparative testing, evaluate whether this affects how quickly the items biodegrade.

Build and maintain a classroom/school compost bin, working with the cafeteria staff and grounds crew.

Additional Multimedia Support

Check out the slide show about composting for kids at http://aggie-horticulture.tamu.edu/kindergarden/kidscompost/cover.html

References

Blashfield, Jean F. and Wallace B. Black. Recycling (SOS Earth Alert). Childrens Press, Inc., 1991.

Cole, Joanna. The Magic School Bus Meets the Rot Squad: A Book about Decomposition. New York, NY: Scholastic Inc., 1995.

Goodman, Billy. A Kid's Guide to How to Save the Planet. New York, NY: Avon Books, 1990.

Prentice Hall Science. Ecology Earth's Natural Resources Activity Book. New Jersey: Prentice Hall, Inc., 1993.

Copyright

© 2005 by Regents of the University of Colorado

Contributors

Amy Kolenbrander; Jessica Todd; Malinda Schaefer Zarske; Janet Yowell

Supporting Program

Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

Acknowledgements

The contents of this digital library curriculum were developed under grants from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation (GK-12 grant no. 0338326). However, these contents do not necessarily represent the policies of the DOE or NSF, and you should not assume endorsement by the federal government.

Last modified: August 17, 2019

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