Dr. Skip's Corner: K-12 Teaching Adventures @ OSU Engineering
November 2004

Plastics in Daily Life

Dr. Skip Rochefort and Eric Mock, Chemical Engineering Department, OSU

Overview
This activity will give students an understanding of the wide use of plastics.  They will learn about some of the properties of different types of plastics, and what the recycling codes are for the big six plastics.

Benchmarks (Grade level K-8)
Science:
Level I (Grade K-2):
        Standard 8: Understands the structure and properties of matter.

Benchmark 1: Knows that different objects are made up of many different types of materials (e.g., cloth, paper, wood, metal) and have many different observable properties (e.g., color, size, shape, weight).
Benchmark 2: Knows that things can be done to materials to change some of their properties (e.g., heating, freezing, mixing, cutting, dissolving, bending), but not all materials respond the same way to what is done to them.

Technology:
Level I (Grade K-2):
        Standard 12: Understands the nature of scientific inquiry.

Benchmark 1: Knows that learning can come from careful observations and simple experiments.

Level II (Grade 3-5):
        Standard 12: Understands the nature of scientific inquiry.

Benchmark 1: Knows that scientific investigations involve asking and answering a question and comparing the answer to what scientists already know about the world.

Level III (Grade 6-8):
        Standard 12: Understands the nature of scientific inquiry.

Benchmark 1: Knows that there is no fixed procedure called "the scientific method," but that investigations involve systematic observations, carefully collected, relevant evidence, logical reasoning, and some imagination in developing hypotheses and explanations.

Objectives
Students will understand that many items they use in daily life contain plastics.  Students will also recognize the variety of properties of these plastics, and will be able to identify the big six plastics based on their recycling code and/or properties.

Materials
Handouts, various different types of plastic (soda bottles, yogurt containers, etc.)

Activity Time
1 hour

Activity: Plastics In Daily Life

There are six major plastics produced in the United States, and as a group they are known as the big six plastics.  Each of the big six plastics has a recycling code, along with unique properties.  These recycling codes and properties, along with the monomer that makes the polymer are given in Table 2 below.

Activity

  1. Ask students in advance to bring one example of each of the big six plastics to class.
    -Alternative: Teacher may supply large group f plastics and have students collect items.
  2. Break students into groups, or have them work individually.
  3. Give students a few minutes to write down all items that they used in the last week that did not contain plastic.
  4. Give students a few minutes to write down all items that they used in the last week that did contain plastic.
  5. As a class, compile an overall list.
  6. Have each group fill out the attached worksheet using the plastics they have brought from home or have acquired in class. Have them Reference Table 1. for uses of recycled plastics.
  7. Set some plastic items in front of the students, and without allowing them to look at the recycling code, see if they can guess what type of plastic it is made from.

Plastics in Daily Life Worksheet
A. General description

  1. Hard or soft?
  2. Color?
  3. Opaque or transparent?

B. Strength

  1. Can you break it?
  2. Does it stretch?
  3. Can you bend it or fold it?
  4. Can you twist it?

C. Uses-share samples with class mates

Sample Plastic Name General Description Strength Uses Recycle Uses
Table 1: Common Uses of the Big Six Plastics
Resin Name Uses

Recycled Products

Polyethylene Terephthalate

Plastic soft drink bottles, mouthwash bottles, peanut butter and salad dressing containers

Liquid soap bottles, strapping, fiberfill for winter coats, surfboards, paint brushes, fuzz on tennis balls, soft drink bottles, film, egg cartons, skis, carpets, boats

High Density Polyethylene

Milk, water and juice containers, grocery bags, toys, liquid detergent bottles

Soft drink bottle base cups, flower pots, drain pipes, signs, stadium seats, trash cans, recycling bins, traffic barrier cones, golf bag liners, detergent bottles, toys

Polyvinyl Chloride

Clear food packaging, shampoo bottles

Floor mats, pipes, hose, mud flaps

Low Density Polyethylene

Bread bags, frozen food bags, grocery bags

Garbage can liners, grocery bags, multipurpose bags

Polypropylene

Ketchup bottles, yogurt containers and margarine tubs, medicine bottles

Manhole steps, paint buckets, videocassette storage cases, ice scrapers, fast food trays, lawn mower wheels, automobile batter parts

Polystyrene

Videocassette cases, compact disc jackets, coffee cups, knives, spoons and forks, cafeteria trays, grocery store meat trays, and fast food sandwich containers

License plate holders, golf course and septic tank drainage systems, desk top accessories, hanging files, food service trays, flower pots, trash cans, videocassettes

TABLE 2. The Big Six Recycling Plastics

Plastic Identification Code

Name of plastic

Description

Monomer

Polyethylene
terephthalate
PET

Clear tough plastic, may be used as a fibre.

Ethylene glycol

C2H6O2

Terepthalic acid

C8H6O4

High density
polyethylene
HDPE

Very common plastic, usually white or coloured.

Ethylene

C2H4

Unplasticised
polyvinyl chloride
UPVC

Hard rigid plastic, may be clear.

Vinyl chloride

C2H3Cl

Plasticised polyvinyl
chloride
PPVC

Flexible, clear, elastic plastic.

Low density
polyethylene
LDPE

Soft, flexible plastic.

Ethylene

C2H4

Polypropylene PP

Hard, but flexible plastic - many uses.

Propylene

C3H6

Polystyrene PS

Rigid, brittle plastic. May be clear, glassy.

Styrene

C8H8

EPS

Foamed, lightweight, energy absorbing, thermal insulation