Glencoe Earth Science

Unit 6: You and the Environment




How many times each day do you use something made out of plastic? From a toothbrush to a soda pop bottle, from a grocery bag to a garden hose, plastics are part of our daily lives. You probably know that plastics are made from petroleum, a nonrenewable resource. When plastics are thrown away, they become part of the solid wastes that end up in sanitary landfills. Today, many solid wastes, including glass, paper, and aluminum, are being recycled rather than thrown away. Some communities are choosing to recycle plastics as well. However, recycling plastics is a bit more complicated than recycling glass, paper, or aluminum.

There are many different types of plastics, and each type requires different handling in the recycling process. The next time you pick up a milk jug or 2-liter plastic soft drink bottle, look at the bottom. Do you see a triangle made out of three arrows? This symbol means that the plastic can be recycled. Inside the triangle you will see a number or perhaps an acronym made up of several capital letters. The numbers and acronyms are part of a coding system that identifies what type of plastic the item is made out of, and how it should be handled in the recycling process. What exactly is a plastic? What are the different kinds of plastics? What is each type of plastic used for? How can each type of plastic be recycled? These are some of the questions you will be able to answer when you have completed this WebQuest on recycling plastics.



Your job in this WebQuest is to learn about the different types of plastics and how they can be recycled. You will explore the history of plastics and find out what properties make a material a plastic. You will identify the seven different classes of plastics, and discover what each class is normally used for. You will also learn what kinds of items can be made from recycled plastics. Finally, you will fill out a table that lists all of the information you have learned about recycling plastics.



Look at the Web sites given here to find the information that will enable you to complete the table on recycling plastics.

  • Hands On Plastics: Background Information for Students.
    Visit this site by the American Plastics Council to learn about the history of plastics and polymers and about the chemistry of the polymers that make up plastics. This is an excellent site to begin your exploration of plastics.
  • Cleaning Up the Waste Stream – Recycling Plastics.
    Visit this site for a brief discussion of the difficulties inherent in recycling plastics. Scroll down to see a chart of the plastic container code system and a description of each type of plastic that can be recycled.
  • Recycling Plastics is as easy as …1, 2, 3 (4, 5, 6, 7)!
    Go to this New York State Department of Environmental Conservation site to see another list of the codes used to identify types of plastic for recycling. The site also describes two methods by which plastic containers are made – blow-molding and injection molding.
  • Recycling Plastics.
    At this Colorado School of Mines site you can read a brief discussion of how plastics are made, and about the chemistry of plastics. You can also read about the benefits of using plastic packaging here.
  • History of Plastics.
    Visit this site to learn more about the history of the plastics industry. The site discusses the inventions of materials such as celluloid, bakelite, rayon, cellophane, nylon, polyvinyl chloride, saran, teflon, and polyethylene.



1 class period for research and filling in the table



Now that you have completed your Internet research on recycling plastics, prepare a table that lists all seven types of plastics. In the left column, write in the code for each of the seven plastics. At the top of the rows, write in the material that each code stands for and the abbreviation used for that type of plastic, then the items the plastic is normally used to make. In the last row, write in what the plastic can be recycled to make. The table is started for you below. You will receive extra points for listing more than one item under how normally used and can be recycled as, up to a total of six items under each heading.

Table 1. Recycling Plastics

CodeMaterial & AbbreviationHow Normally UsedCan Be Recycled As
22 Polyethylene teraphthalate,PET, PETEsoft drink bottlessoft drink bottles, paint brushes,
carpeting, egg cartons
2High density polyethylene

Complete the table by adding the appropriate information for all seven types of plastic.



In the process of completing this WebQuest, you’ve become informed about what plastics are, what types of plastics exist, and how each of these can be recycled. You have learned a little about the history of plastics, and about the chemistry behind the plastics that you use every day. Finally, you have completed a table that lists each type of plastic, what each is normally used for, and what items each type of plastic can be recycled into. How does recycling plastics compare to recycling of materials such as glass, paper, and aluminum?



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