Hands-on Activity: Trash to Treasure!

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

A drawing of a footprint filled with trash, including recyclable/reusable items.
Trash is just a resource that we haven't found a use for...
Copyright © State of Connecticut, Department of Environmental Protection http://www.kids.ct.gov/dep/cwp/view.asp?a=2714&q=432260&depNAV_GID=1645


Student teams use the engineering design process to create a useful product of their choice out of recyclable items and "trash." The class is given a "landfill" of reusable items, such as aluminum cans, cardboard, paper, juice boxes, chip bags, egg cartons, milk cartons, etc., and each group is allowed a limited amount of bonding materials, such as duct tape, hot glue and string. This activity addresses the importance of reuse and encourages students to look at ways they can reuse items they would otherwise throw away.

Engineering Connection

Engineering plays an important role in our environment. Our landfills are filling up faster and faster and pollution levels are getting higher and higher. Designing projects from a global perspective including low-energy manufacturing, renewable sources and utilizing recyclable and reusable materials is critical to decrease our pollution levels for a cleaner, healthier planet.

Pre-Req Knowledge

A basic understanding of the engineering design process (see https://www.teachengineering.org/engrdesignprocess.php). Completion of the Global Climate Change lesson if the teacher wishes for the students to have a good understanding of global warming.

Learning Objectives

After this activity, students should be able to:

  • List harmful consequences of global warming.
  • Explain how recycling and reusing helps cut down on greenhouse gases.
  • List ways to reuse items before discarding them.
  • Use the engineering design process to create a product from reused materials.

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Let's Heat Things Up!

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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.

  • Fluently add, subtract, multiply, and divide multi-digit decimals using the standard algorithm for each operation. (Grade 6) Details... View more aligned curriculum... Do you agree with this alignment?
  • Solve unit rate problems including those involving unit pricing and constant speed. (Grade 6) Details... View more aligned curriculum... Do you agree with this alignment?
  • Summarize numerical data sets in relation to their context, such as by: (Grade 6) Details... View more aligned curriculum... Do you agree with this alignment?
  • The management of waste produced by technological systems is an important societal issue. (Grades 6 - 8) Details... View more aligned curriculum... Do you agree with this alignment?
  • Decisions to develop and use technologies often put environmental and economic concerns in direct competition with one another. (Grades 6 - 8) Details... View more aligned curriculum... Do you agree with this alignment?
  • Solve real-world and mathematical problems involving the four operations with rational numbers. (Grade 7) Details... View more aligned curriculum... Do you agree with this alignment?
  • Develop, communicate and justify an evidence-based scientific explanation to account for Earth's different climates (Grade 8) Details... View more aligned curriculum... Do you agree with this alignment?
  • Research and evaluate direct and indirect evidence to explain how climates vary from one location to another on Earth (Grade 8) Details... View more aligned curriculum... Do you agree with this alignment?
Suggest an alignment not listed above

Materials List

Each group needs:

  • duct tape, 12 inches (~30 cm)
  • string, 12 inches (~30 cm)
  • glue, or hot glue gun and glue sticks

To share with the entire class:

  • aluminum cans (note: cans are very sharp when cut and may need to be omitted from the materials list or used with a rule that the aluminum cans cannot be cut)
  • used copy/scrap paper
  • newspaper
  • used cardboard
  • egg cartons
  • (rinsed out) plastic bottles
  • chip bags
  • (rinsed out) drink boxes
  • other miscellaneous recyclable/used items


Our climate is changing as we speak, and within your lifetime, the Earth could become 2-4°F warmer! The Earth has already warmed by about 1°F during the past 100 years. Many scientists think this is due to human activities and impact on the planet, and they expect the average global temperature to increase an additional 2-6°F over the next 100 years. While we do not know exactly what the result of these small changes in temperature might be, scientists have made some predictions. Rising temperatures could melt ice caps at the Earth's poles, causing sea levels to rise, which in turn could cause flooding in coastal regions. Plants and animals in fragile ecosystems may find it difficult to adapt to warmer temperatures. And, people will have to get used to an increased number of hot days each year, and more erratic weather patterns.

Fortunately, policy makers and engineers are taking precautions to try to slow down global warming. The release of greenhouse gases is an important thing to remember in engineering design. We must be aware of how much pollution results from the manufacture of all the products that engineers design. Today, you will all act as engineers responsible for designing products made entirely out of used items. How does this help keep pollution levels low? It helps save our resources — such as trees, oil and coal — that would be used to build a new product as well as puts fewer products in our landfills, which lowers the greenhouse gas caused by decomposing garbage.

How do we prevent the planet from overheating? We must prevent greenhouse gases from being overproduced. Can you think of things we do every day that create greenhouse gas, such as carbon dioxide? (Possible answers: Driving our cars or using too much electricity that was generated by burning fossil fuels. See the associated lesson for more ideas.)

Engineers can help us rethink the way we do these things so that we can reduce the amount of greenhouse gases we produce. For example, engineers are designing more efficient cars that use less gas and produce fewer greenhouse emissions. Engineers can also create products that can be reused more often, or they can create products using materials that have already been used by other people — just like you will do today.


climate change: The change in long-term weather patterns; changes can cause warmer or colder temperatures; annual amounts of rainfall or snowfall can increase or decrease.

global warming: Refers to an average increase in the Earth's temperature, which in turn causes changes in climate; a warmer Earth may lead to changes in rainfall patterns, a rise in sea level, and a wide range of impacts on plants, wildlife, and humans.

greenhouse effect: The effect produced as greenhouse gases allow energy from the sun to pass through the Earth's atmosphere, but prevent most of the outgoing heat from the surface and lower atmosphere from escaping into outer space.

recycle: The reprocessing of used materials that would otherwise become waste by breaking them down and remaking them into new products.

reuse: Putting an item to another use after its original purpose has been fulfilled; reusing an item for the same purpose over and over, such as refilling a water bottle, or for a new purpose such as using empty grocery bags as garbage can liners.


Before the Activity

  • A few weeks before starting this activity, place a large container in the classroom for students to start filling up with items they would otherwise throw away or recycle. Make sure cans are rinsed and no food items go into the materials box.
  • Gather materials.
  • Discuss how recycling affects the production of greenhouse gases and the importance of reducing pollution that impacts the environment and our global. (Refer to the associated Global Climate Change lesson.)
  • Make copies of the Carbon Footprint Worksheet, one per group.

With the Students

  1. Divide the class into groups of two to four students each and give them the problem statement: As a group, build a product with the following criteria:

-Use only materials listed in the materials list. (These should be all reused materials, plus the limited amount of bonding materials.)

-The product must be useful (that is, not be an artistic sculpture, decoration, etc.).

-A minimum of three items must be used.

  1. Ask students to brainstorm ideas in their groups and create an engineering drawing of their design. Give them a limited amount of time, perhaps 15 minutes.
  2. After their drawings are reviewed by the teacher, they can start construction.
  3. Once every group's product is finished, ask each group to present to the class a description and demonstration of its design and and how it can be used. (Note: Students should trade off speaking roles within their group; that is, one student tells the name of the product, another students describes what it is used for, etc.).


Safety Issues

Make it a rule that the aluminum cans may not be cut since their edges are extremely sharp and dangerous.


Pre-Activity Assessment

Discussion Question: Solicit, integrate and summarize student responses. How does recycling and reusing help our environment? Why do you think people do not recycle more often? See Table 1 for possible answers.

Reusing advantages include energy and material savings, reduced disposal / and costs. Disadvantages include transport is required, containers must be cleaned, reusable products need to be made more durable than disposable ones. Recycling advantages are keeping waste out of landfills, reducing consumption and costs associated with getting new raw materials, lowered costs and fewer pollutants from starting with recycled materials. Disadvantages are energy for transportation and processing of recycled materials and other costs associated with the recycling process.
Table 1. The advantages and disadvantages of recycling and reusing.
Copyright © ITL Program, University of Colorado at Boulder

Activity Embedded Assessment

Brainstorming: In design groups, have students engage in open discussion on ideas for their product designs. Remind them that in brainstorming, no idea or suggestion is "silly." All ideas should be respectfully heard. Take an uncritical position, encourage wild ideas and discourage criticism of ideas. Ask students to write down all their ideas and then agree on a design together.

Post-Activity Assessment

After completion of the worksheets, as a class compute the class mean footprint and discuss why some students have larger or smaller numbers.

Concept Reflections / Journal Writing: Have students reflect on the waste that they create on a daily basis. Ask them:

  • How much waste do you think you create each day?
  • What kinds of things do you throw away?
  • Which of these could be recycled instead of thrown away?
  • How could you change your habits to reuse more materials?

Activity Extensions

Discuss other ways that items we throw away could be reused. Examples: old snowboard used for benches, an old can used for a pencil holder, etc. Then, ask students to draw something they could utilize at home that was made out of used materials. Have them label the picture with the materials they would need to build it. Ask each student to present their designs to the class.

Activity Scaling

  • For lower grades, scale down the activity by providing more bonding materials to ease the construction process.
  • For upper grades, give students more difficult requirements such as building a chair that must be able to hold a certain amount of weight, etc.


State of Connecticut, Department of Environmental Protection, "Climate Change and Waste," June 10, 2009, accessed June 22, 2009. http://www.kids.ct.gov/dep/cwp/view.asp?a=2714&q=432260&depNAV_GID=1645

Colorado State University, Center for Science, Mathematics and Technology Education (CSMATE), CLTW West, Center For Learning & Teaching In The West (CLTW), Colorado Science & Mathematics Professional Development Web Site, "Your 'Footprint' on the Global Environment – The Greenhouse Effect," accessed June 22, 2009. http://www.news.colostate.edu/Release/5774


Christie Chatterley; Marissa Forbes; Malinda Schaefer Zarske; Janet Yowell; Karen King; Denise W. Carlson


© 2009 by Regents of the University of Colorado.

Supporting Program

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


The contents of this digital library curriculum were developed under a grant 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 Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: August 10, 2017