Summary

In this lesson, students will develop an understanding of the chemistry of plastics and apply their knowledge in order to engineer a cost effective and environmentally friendly method to clean up the Great Pacific Garbage Patch.

Grade Level

Middle School and High School

NGSS Alignment

This lesson will help prepare your students to meet the performance expectations in the following standards:

• HS-ETS1-3: Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.
• MS-PS1-3: Gather and make sense of information to describe that synthetic materials come from natural resources and impact society.
• MS-ESS3-3: Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.
• Scientific and Engineering Practices:
  • Asking Questions and Defining Problems
  • Constructing Explanations and Designing Solutions
  • Obtaining, Evaluating, and Communicating Information

Objectives

By the end of this lesson, students should be able to

• Discuss the structure of polymers (plastics) and relate the structure of polymers (plastics) to function and properties exhibited by polymers.
• Design a possible solution to complex real-world problem and engage in a discussion based on evidence and research to evaluate possible solutions.

Chemistry Topics

This lesson supports students’ understanding of

• Polymers
• Environment Science

Time

Teacher Preparation: 5 minutes

Lesson: 60-90 minutes

Materials

• Student handout (included)
• Ruler
• Calculator
• Colored pencils

Safety

• No specific safety precautions need to be observed for this activity.

Teacher Notes

• Day 1:
• Start the lesson with a discussion on plastics (polymers). Topics for discussion should include:
  • How plastics are made
  • Structure of plastics
  • Properties of plastics
• The grade level and ability of your students should determine the scope and depth of the discussion. For example:
  • At the middle school level the discussion will focus more on the properties of plastics and why plastics take a great deal of time to degrade in the environment.
  • At the high school level, the activity can be used to start a discussion on polymers and organic chemistry.
  • For both grade levels get students to discuss just how much they use plastics and how they have changed civilization.
• ­­Use the Plastic History and Chemistry link to access a very informative website about the history and chemistry of plastics.
• Use the AACT lesson plan, The Right Polymer for the Job to further reinforce polymer concepts if necessary.
• Following the discussion of plastics and polymers, show the video to introduce students to the Great Pacific Garbage Patch.
• Some interesting facts to share with students about the Pacific garbage patch:
  • Around the world, about 18 billion pounds of plastic waste flow into our oceans each year. The average American throws away about 185 pounds annually (national geographic).
  • The plastic island has grown to be twice the size of Texas. Texas area is 269,000 square miles (697,000 square kilometers) and continues to grow.
  • Trash Travels estimates that plastic bags can take 20 years to decompose, plastic bottles up to 450 years, and fishing line, 600 years; but in fact, no one really knows how long plastics will remain in the ocean (Cho).
• Introduce the student activity “Cleaning-up the Plastic Island” to the students. Students should start the activity by reading the scenario on the student document. After reading scenario the students will complete part 1 of the activity. The goal of part 1 of the activity is to help students understand the tremendous size of the plastic island.
  
• Student Activity Part 1: Understanding the Size of Plastic Island
  
  • High School level: Inform the students that the island spans 269,000 square miles (697000 km²). Do not tell the students that the island is twice the size of Texas. The students should create a rectangle of the same area on the map of the United States using the distance scale on the map provided. After the students have completed this section of the activity, inform them the area of the plastic island is twice the size of Texas.
  • Middle School Level: Remind the students that island spans 269,000 square miles and is twice the size of Texas. Students should work in pairs. Have the student follow the instructions on the student document.
• Student Activity Part 2: Cleaning up the Plastic Island
  
  • The procedure of part 2 will be the same middle school and high school level.
  • Students should work in pairs or groups (2-4) for this part of activity. The pairs/groups should design a detailed method to clean up the Pacific plastic island. Remind students to consider cost, scope, constraints, and feasibility of their method.
• To end day 1 of the activity, project a picture of the plastic island (many more images available via Google) to remind students of the scope of their task.
  
• Closure: Close the lesson at the high school level with a quick review of the structure and important properties of polymers. For the middle school lesson, have students finish the “exit ticket” questions on the student document.

• Day 2:
• Allow students to continue to design and evaluate their method that they began in Part 2 of the Student Activity. Students should produce a detailed written (typed if preferred) copy of their plan for submission.
• After all of the groups have completed their plans, ask each group to briefly present and share their idea with the class. Create a list on the board which quickly summarizes each group’s plan for analysis.
• Allow students to politely critique and evaluate each group’s plan as a class. The goal of the critiquing process is to discover potential flaws and obstacles present in the plans. At the end of the sharing and critiquing process, as a class determine one final master plan to clean up the plastic island.
• Example of some common flaws:
  • Using a net to scoop up the plastic would require too many boats (manpower) and too many trips (fuel costs) to land to empty the collected trash.
  • Bringing the trash to land doesn’t get rid of the trash, just moves the problem. What will you do with all the plastic now that it is on land?
  • Breaking down the plastic into smaller pieces is an environmental hazard (fish may eat the plastic mistaking it for a food source).
• Follow-up Discussion:
  • After the class forms their unified plan to clean up the plastic island. Discuss some modern ideas and theories on how the plastic may be removed. Use the links below to access articles about an accidental enzyme known to break down plastic and a teen inventor who devised a method to reduce the amount of plastic flowing in the ocean.
  • Mutant Enzyme
  • Teen Inventor