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Akron Global Polymer Academy Lesson Plans

The Stress of being a Recycled Bag

Grades: 6-12
Author: Joseph DeAngelis
Source: This material is based upon work supported by the National Science Foundation under Grant No. EEC-1161732.


Students will test the tensile strength of a shopping bag and discover that the polyethylene film has a higher tensile strength when pulled parallel with the extrusion lines then when pulled perpendicular to the extrusion lines. The students then apply what they learn to design an experiment to compare the strength a shopping bag made from recycled polyethylene to one that contains no recycled material. This lesson can be done with common inexpensive materials which may be collected from the home. Teacher Notes attached


What should students know as a result of this lesson?

What should the students be able to do as a result of this lesson?


(For each group of students)



Introduce polymers

Take pre-assessment


Test the tensile strength of a plastic bag and share results


Class discussion about the results of the tensile strength activity

Teacher explanation based on results


Show "The Magnificent Plastic Bag" youtube video and discuss the importance of recycling.

Students now test a bag made with recycled HDPE and a bag not made with recycled HDPE.

Students are assessed through a presentation of their findings and a post-assessment.


The students should know the basic types of chemical bonds - ionic and covalent.

The students should know that physical properties depend upon structure

Best Teaching Practices

Alignment with Standards

NGSS Standards:

Common Core Standards:

National Standards:

Ohio Standards:

Content Knowledge

The testing of the properties of materials is an ongoing part of modern technology.

The development of improved methods of collecting and recycling materials.

The development of biodegradable materials.


Follow General laboratory safety - there are no hazardous materials used in this lab.

Caution should be taken when using sharp scissors.

Water spilled from the tensile test may create a slippery floor and walking hazard.


Materials structure determines function.

Recycling materials and ecological responsibility of consumers.


The pre-assessment and post-assessment

Group presentation of "Stress of a Recycled Bag" activity

Other Considerations

Lesson Sequence: (based on 50 minute periods)

Printable PDF Worksheets



Determining the Tensile Strength of Polyethylene Film

The Stress of a Recycled Bag with Presentation Rubric

Teacher Notes