SOIL, A Design You’ll Dig: Designing a Habitat for Worms

By Cooper-Hewitt National Design Museum, April 5, 2010

Grade Level

  • Middle School

Category

  • Architecture

Subject Area

  • Language Arts
  • Science

Lesson Time

2.5 hours

Introduction

Under our feet and in the soil, worms are converting organic wastes into the vital nutrients our planet depends upon every day. This process of decomposition is an essential part of the nutrient cycle, renewing the health of our landscape and playing a large role in keeping our environment in balance. Worms are found on nearly every continent and literally build the soil below our feet.
Worms dig through the earth, decomposing organic waste into rich soil.
They help turn wastes into soil. Organic wastes like fallen leaves, food scraps and paper comprise nearly 15-20% of the volume found in landfills around the country.  This waste can easily be broken down through a process of vermicomposting, the process of worms converting our wastes into soil.
 
Designers around the world are inventing ingenious ways to mimic the process that worms provide our earth in many ways, from anaerobic digesting systems to “worm condos”. In this lesson, students will design a habitat for worms that will serve as composters for their home or school. Students will learn about composting, nutrient cycles and the importance of decomposition in their local environment. This exercise will compliment many language arts lessons, helping students evaluate data, participate in society and communicate effectively about a design and ecological concept.

National Standards

 
 
 
Common Core Mathematics
 
 
Language Arts
Level III (Grade 6-8)
 
 
Science
Benchmark 1.  Knows that all individuals of a species that exist together at a given place and time make up a population, and all populations living together and the physical factors with which they interact compose an ecosystem Benchmark 2.  Knows factors that affect the number and types of organisms an ecosystem can support (e.g., available resources; abiotic factors such as quantity of light and water, range of temperatures, and soil composition; disease; competition from other organisms within the ecosystem; predation)  Benchmark 5.  Knows how matter is recycled within ecosystems (e.g., matter is transferred from one organism to another repeatedly, and between organisms and their physical environment; the total amount of matter remains constant, even though its form and location change)
 
Health
Level III (Grade 6-8)

Objectives

  •  Students will design a habitat for worms that will serve as a composter for their classroom
  •  Students will understand the nutrient cycle and decomposition process
  •  Students will use design thinking to create a habitat for worms
  •  Students will understand the environmental benefits of composting and organic waste reduction in the school and community
 

Resources

Materials

Redworms, Food scraps, Newspaper (Soy-based inks), Brown Paper, Plastic bins, Black (non-toxic) paint, Screen material
 

Vocabulary

  •  Annelida - segmented worms: earthworms; lugworms; leeches 
  •  Decomposition - Decomposition is the process by which tissues of a dead organism break down into simpler forms of matter
  •  Vermicompost - Vermicompost is the product or process of composting, utilizing various species of worms, specifically red wigglers, white worms, and earthworms creating the heterogeneous mixture of decomposing vegetable or food waste, bedding materials, and pure vermicast produced during the course of normal vermiculture operations.

Procedures

The Nutrient Cycle! (10 minutes – Review)
Begin your lesson with a brief discussion of the nutrient cycle. 
In ecology the nutrient cycle is a pathway by which a chemical element or molecule moves through compartments of earth. In effect, the element is recycled. In the nitrogen (N) cycle, organic nitrogen exists in materials formed from animal, human, and plant activities that produce manures, sewage waste, compost, and decomposing roots or leaves. These organic products transform into organic soil material called humus. Nitrogen is a primary element in soil and is an essential nutrient for plant growth.
 
Millions of microorganisms live in most soils, most too small to see with the naked eye. They eat organic matter such as grass clippings, fallen plant leaves, and algae. In doing so, they reduce dead organic matter on Earth's surface and release nutrients from the decomposing organic matter for living plants to use. One of the most common organisms found in the soil are worms. Worms are a part of the phylum Annelida. Earthworms in particular are classified into three main categories: (1) leaf litter/compost dwelling worms (epigeic), (2) topsoil or subsoil dwelling worms (endogeics); and (3) worms that construct permanent deep burrows through which they visit the surface to obtain plant material for food, such as leaves (anecic). 
 
Explain that today's  topic is leaf litter or compost dwelling worms. You can setup a simple observation/experiment by bringing in fresh leaf litter (leaves and brush) and some soil for students to observe. Divide students into teams and setup trays with leaf litter and soil. Provide spoons and hand lens for students to observe worms in their natural habitat. Encourage respect for the worms, some students may try to harm or kill the worms.
 
Environmental Impacts and Solutions: From Leachate to Compost (10 minutes - Investigate)
After engaging in a worm observation activity, talk about organic wastes. What is organic waste? Things like food scraps, leaves and other wastes that were once alive. Where do these wastes go? Commonly, they get thrown in the garbage and end up in landfills. In many communities organic wastes are 10-20 percent of the volume of a landfill. When these wastes are thrown into a landfill the organic matter breaks down. When combined with water and other chemicals that can collect in the landfill, a harmful substance is formed called leachate. Leachate is the liquid that drains or 'leaches' from a landfill; it varies widely in composition regarding the age of the landfill and the type of waste that it contains. Leachate can produce methane and other gases that affect air quality and make the landfill dangerous because the gases are explosive.
 
So this system of throwing away organic matter presents many problems – wasted space in landfills, toxic leachate and worst of all, we are wasting a resource that could be used to help fertilize gardens or food crops!
 
What’s the solution? Composting! Composting is the process of breaking down organic matter into a useable fertilizer that can be utilized as a nutrient source for plants. The problem with setting up a composting system in many homes and schools setting is a challenge of DESIGN! Facilities like classrooms, kitchens and other spaces are not designed to compost organic wastes, and because of this it is usually not attempted or becomes difficult to integrate into existing designs.
Simple wooden bins such as the one pictured above are commonly used for composting.
In this activity, we are going to use a popular form of composting.  Vermicomposting – or using red worms to help speed up the composting process and break down organic wastes faster. Vermicomposting is a great way to compost indoors, saving space and reducing odors. 
 
Your challenge in this activity is to design a composting system for your classroom that addresses common design challenges that impact the use of composting in your school. 
 
Local Connections (10 minutes - Frame/ReFrame)
To begin addressing this design challenge with students, start by investigating your school building and classroom. What kinds of problems do you see with how the space in your classroom is designed? Is it set up for compost? What about the cafeteria? Have students investigate this problem in relationship to their school. Ask each student or teams of students to conduct research that can help fill out the following table:

Area of the School

Challenge

Observation

Potential Solution

Cafeteria

Lots of food wastes thrown away

 

 

Classrooms

 

 

 

Hallways

 

 

 

Library

 

 

 

Gym

 

 

 

Teachers Lounge

 

 

 

Bathrooms

 

 

 

Other Areas

 

 

 

Also discuss with students some examples of materials designed for easy breakdown through the composting process referenced in the 2010 National Design Triennial:
 
 AgroResin: AgroResin is a sustainable packaging material that can be made from any type of plant fiber including rice and wheat straw, corn stalk, and residue from cotton and sugarcane harvesting—that would otherwise be incinerated or dumped in a landfill. AgroResin can be recycled like paper or composted.
• Bioware Packaging: Bioware, a biodegradable packaging material and dinnerware made from bagasse, or the fibrous remains after sugarcane is crushed. This environmentally-friendly material is engineered to biodegrade in forty-five days.
• Kraftplex: Kraftplex is a 100% biodegradable alternative to plastic and metal sheeting.
• PLMS6040 Compostable Polymer: Kareline’s PLMS is a natural, fiber-reinforced PLA (polylactic acid) that is biodegradable and has applications for consumer electronics, packaging, toys, and other goods
 
Compost Design Lab: Part One (20 minutes – Generate)
After investigating the situation locally, it’s time for a design-challenge. Divide your students into design teams of 4-5 students each.
 
Each team will be challenged to design their own composting system for a classroom in the school. Teams will be given the following criteria and asked to design a vermicompost unit:
 
1. The unit must remain at or around 65 degrees Fahrenheit
2. The composter has to remain dark with a minimal amount of sunlight reaching the confines of the unit
3. The unit should have proper ventilation (using screens is a good idea)
4. It should be easily accessible and identifiable for students/teachers to use (ie. Lid should come off easily, signs of what you can put in the composter and what you can’t should be available as well)
5. Has to be able to be emptied easily
6. Has a chamber for liquid drainage/collection
 
Ask students to first brainstorm and then to sketch out some designs. Ask them to consider this as a habitat for worms – ie. what would make a good home for them? Ask each student to also write a story from the worm’s perspective about his or her new home.
 
What is compostable?

banana skins

leather

feathers

grains

flour

rice

stale bread

grass clippings

newsprint (soy based ink)

manures

egg shells

oatmeal

wood chips

old seed packets

flour

seaweed

fish scraps (buried)

straw and hay

powdered milk

tobacco

pine needles

stale cereal

hair (human, animal)

wood shavings

natural fibers (cotton, linen, wool)

rock powder (greensand, granite dust)

coffee grounds (with paper filter)

dead insects

tea bags

crop waste

cornmeal

paper/cardboard

flowers

bone meal

seashells (crushed)

peanut shells

cottonseed meal

kitchen scraps

yard waste

watermelon rind

vacuum bag wastes

potato peels

leaves

sawdust (not treated)

shredded hardwood

corncobs

ground bones

bird cage "stuff"

old potting soil/mix

weeds (most, but not all)

fruits & vegetables

DO NOT COMPOST: Meat and dairy products, oils, bones, treated wood, colored newsprint that is not soy-based
 
Compost Design Lab: Part Two (20 minutes - Edit and Develop)
If materials and time allow – each design team should construct a working model of their composting unit. Provide students with opaque storage bins, mesh for ventilation, newspaper and brown paper scraps, leaf litter and other materials needed for each design.
 
Help each team construct their unit. Spend 1-2 weeks testing out the composting units and see if they are effective. Review school composting manuals online (http://www.ct.gov/deep/lib/deep/compost/compost_pdf/schmanual.pdf)
 
Finally, after testing out the units, share your final designs with other classes. Set up designated worm habitat areas in classrooms around the school. Mobilize with sanitation staff to create a working composting system for the school. Maintenance and upkeep are the most essential elements of any composting system. (Share and Evaluate)
 
 

Assessment

Reflection Questions
  • What is your favorite aspect of your design and how will it benefit the worms who live in it?
  • Why are natural decomposition processes important for your everyday life?
  • How would you have to change your behavior to maintain a worm farm in the long term?
  • Do you think your design is large enough to hold all of the organic waste that you produce?

Enrichment Extension Activities

Differentiation for Elementary School:
  • An adult (teacher, student teacher, aide, parent volunteer) can assist with each group as they conduct their research of composting challenges in their school. You might focus on the cafeteria and classrooms only.
  • Students can write a story or song, draw or create a play from the worm’s perspective about his or her new home.
  • Students can brainstorm in groups about best design solutions. Groups can then come together as a class to discuss their ideas. Through class discussion, the teacher can incorporate ideas from each group to produce the most effective design solution. Along with the students, the teacher can then assist in building one compost bin for the entire classroom using ideas presented by the students.
Differentiation for High School:
  • Students can use online sources and scientific journals to complete a research paper on the nutrient cycle, leachate and composting.
  • Student groups can present their research along with their designs to the schools' administration in order to gain buy-in before building composting bins for long-term use by the school.

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