Hands-on Activity Bury Your Trash Experiment

Learning Objectives

After this activity, students should be able to:

• Explain what the term "biodegrade" means, and generally describe how the process works with respect to the various items of buried trash.
• List what objects do and do not biodegrade (roughly) by explaining the difference between organic and inorganic materials.
• Explain how engineers apply what they know to facilitate waste management.

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: Next Generation Science Standards - Science

Common Core State Standards - Math

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

For the entire class:

• 1 patch of ground (earthy, with soil) that can be used to dig holes in, roughly 1.5 m x 1.5 m (5 ft x 5 ft)
• (optional) string, approximately 12 m (40 ft), for marking off ground segments
• 2 small shovels or trowels, to dig up the soil
• assorted trash and pieces of food (have students save their lunch trash)
• 2 large sheets of poster paper
• disposable gloves, pair for each student

Introduction/Motivation

Now that we have talked about what biodegradation is and everyone has collected some trash from lunch, let's go outside. Bring with you what you saved from lunch.

In this patch of land, we will bury individual pieces of trash in a grid pattern. That way, when we dig it up in three months, we can learn what happened to each type of material. Let's use multiplication to figure out how many spots on the grid are available to bury the individual items.

Now, I want everyone to get together to decide which pieces we will bury. Remember, we want to put as many different materials under the soil, so we can determine which materials biodegrade and which ones do not. Try to avoid burying the same type of garbage twice.

Procedure

Before the Activity

• Identify a small area of earthy ground that is located away from foot traffic and obtain permission to be able to dig up and use the area for the next three months.
• Using a sturdy shovel, dig in the soil to turn it over and mix in any grass or plants). Attempt to create a square of churned-up soil approximately 6 inches deep. Use the string to create a grid over the soil with 1 ft x 1 ft squares, by cutting 8 lengths of 5-ft-long string, laying 4 horizontally and equally spaced, and laying 4 vertically in the same manner.

With the Students

1. Instruct students to each save a piece of trash or two from his/her lunch, including sandwich crusts, apple cores, etc. Essentially, tell them they to save whatever is leftover once they have eaten everything they wanted.
2. After lunch and in the classroom, give students gloves and have them sort their various pieces of trash into one long row of items, putting like items together. For example, put paper wrappers, foil wrappers, Styrofoam, cardboard each in their own piles.
3. On a poster board, draw a table with three columns and these row headers: type of garbage, prediction, result. Record the type of each trash pile its own row. Ask students as a group to predict, for each trash type, whether or not they think that material type will biodegrade over the next three months. Record their predictions.
4. Lead the class outside to the prepared soil area. Have students bring pieces of trash they would like to bury. Bring as many different types of trash as possible. As each student buries his or her piece of trash, ask one student draw a grid diagram on another poster board and record where each item is buried in the plot.
5. Two to three months later, or longer if the experiment is performed during the winter months, bring the poster boards, shovel and gloves and go outside with the class and dig up the plot. As each plot is dug up, try to identify what is uncovered. Have the students use descriptive words to explain what the piece of trash now looks like, how it changed, and record the results for each piece of trash.
6. Conclude with a class discussion, asking students the Investigating Questions.

Vocabulary/Definitions

biodegrade: To decay and become absorbed by the environment.

compost: Remnants of organic materials, usually used in gardening.

decompose: Similar to spoiling, the breaking down of larger molecules into smaller molecules.

inorganic matter: Matter not having the structure or organization characteristic of living bodies.

landfill: A site for the disposal of waste materials by burial.

organic matter: Matter that has come from a recently living organism, is capable of decay, or the product of decay.

Assessment

Quiz: Ask students some questions to gauge their comprehension of the subject matter. Have students individually write their answers on paper to be handed in for grading.

• Write out the definition of the term "biodegradable."
• Describe a dump.
• Describe a compost pile.
• Describe what happens to your household garbage after it is "thrown away."
• List the types of materials that are biodegradable and those that are not.
• (Show students a number of new items of trash.) Identify each item as either biodegradable or not biodegradable.

Investigating Questions

• Which types of garbage decomposed? Why do you think they were able to decompose?
• Which types of garbage did not decompose? Why do you think they were not able to decompose?
• Which types of trash were not recognizable? What happened over the last several months that made those pieces of trash change?
• In what ways might the use of biodegradable materials be helpful to the environment?

Safety Issues

• Handling garbage is unsanitary so make sure that the children wear gloves and wash their hands after they move their trash from the cafeteria to the mock landfill.
• Remind students to be careful when handling the small shovels. If they do not know already, instruct them in the correct way to dig up small amounts of soil at a time.

Troubleshooting Tips

It helps to dig up the soil in the grid area before the children dig their own holes. Locating the test plot in a garden area may make moving the soil easier.

Bury as many different types of trash (different materials) as possible, including a lot of organic items that will readily decompose.

Doing this experiment in the warmer months helps the organic objects decay much faster, and reduces the three-month waiting period a good deal.

Activity Extensions

Create a class compost pile, beginning with the dug-up trash remnants that were found to be biodegradable. This reinforces the concepts covered and provides another hands-on experience.

References

Copyright

Contributors

Supporting Program

Acknowledgements

This content was developed by the MUSIC (Math Understanding through Science Integrated with Curriculum) Program in the Pratt School of Engineering at Duke University under National Science Foundation GK-12 grant no. DGE 0338262. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.