IOWA 4-9 SCIENCE PROJECT

TEACHER GUIDE for: Recycling Plastics Lowell Wiele
ECOLOGY.796 Grades 7-9

CONCEPT OBJECTIVE:
The concept developed is how plastics are coded by industry
and how to identify and determine specific plastics for
recycling.

PROCESS OBJECTIVE:
Thinking skills developed in this cycle are measuring,
classifying, exploring, inferring, reporting, valuing, and
decision-making.

TEACHER BACKGROUND:
This learning cycle is open ended and can lead to further
study of properties, polymerization, and technology of
plastics. The exploratory activity involves using heat so
safety rules must be followed. Even though modern plastics
are synthetics build around carbon molecules made from
fossil fuels, the students will explore how some of the
first natural plastics were made. Students should be
familiar with the terms feedstock, fossil fuel, monomer,
polymers, and recycling. Take plenty of time for class
discussions and the home survey.

EXPLORATION:
Students are asked to produce a natural polymer called
casein using the following simple ingredients. Using one
cup of skim milk and two tablespoons of white vinegar the
students will attempt to make natural plastic. Even though
the students are doing an exploratory activity the teacher
will want to direct the students during the beginning of the
activity. The cup of skimmed milk should be heated until it
is near to boiling. The two tablespoons of white vinegar is
next stirred into the milk. Continual stirring should take
place until the mixture thickens and lumps are formed (about
3-5 minutes). The mixture should be removed from the heat
but should be stirred as long as lumps are forming. After
cooling the casein should be removed from the milk and
washed in water. Students can mold the casein into any
shape. In a few days the material will harden into a
natural plastic.

CONCEPT DEVELOPMENT:
Ask the students to give examples of how they use plastics
in their life. This should lead into a class discussion
about our dependency upon plastic. Record examples of
plastic use on the chalkboard. Have the students find
examples of plastics in their home. The students will
survey their home and community to find samples of different
types of plastic. Students should refer to the resin code
sheet as they classify their plastics according to types.
The student activity sheet should be completed by the
students as they record data pertaining to the plastic they
found. Recycling issues should now be discussed in class.
The recycling process including the coding system developed
by the plastics industry should be discussed.

|==========================================================|
| PLASTIC RESIN CODES |
|==========================================================|
| TYPES OF | INDUSTRY | RESIN | TYPICAL PACKAGING |
| PLASTIC |ABBREVIATION| CODE | USES |
|==========================================================|
|Polyethylene | | 1 |Recording tapes, Soda |
|Terephthalate| PET | PETE |& Vegetable bottles |
|_____________|____________|_______|_______________________|
|High-Density | | 2 |Grocery bags, Milk & |
|Polyethylene | HDPE | HDPE |Detergent bottles |
|_____________|____________|_______|_______________________|
|Polyvinyl | | 3 |Floor covering, Water |
|Chloride | PVC | PVC |& Shampoo bottles |
|_____________|____________|_______|_______________________|
|Low-Density | | 4 |Trash bags, Food wrap, |
|Polyethylene | LDPE | LDPE |Toys, & Housewares |
|_____________|____________|_______|_______________________|
|Polypropylene| | 5 |Drinking straws, Toys, |
| | PP | PP |Carpet backing, & Lids |
|_____________|____________|_______|_______________________|
|Polystyrene | | 6 |Appliance parts, Foam |
| | PS | PS |& Clear food containers|
|_____________|____________|_______|_______________________|
|Others | | 7 |Sport, Medicine, & |
| | OTHER | OTHER |Construction Plastics |
|_____________|____________|_______|_______________________|

============================================================
| PLASTICS |
| STUDENT ACTIVITY SHEET |
|__________________________________________________________|
| RESIN | LOCATION | PRODUCT |
| CODE | FOUND | DESCRIPTION |
|_______|_________________________|________________________|
| | | |
| 1 | | |
|_______|_________________________|________________________|
| | | |
| 2 | | |
|_______|_________________________|________________________|
| | | |
| 3 | | |
|_______|_________________________|________________________|
| | | |
| 4 | | |
|_______|_________________________|________________________|
| | | |
| 5 | | |
|_______|_________________________|________________________|
| | | |
| 6 | | |
|_______|_________________________|________________________|
| | | |
| 7 | | |
|_______|_________________________|________________________|

APPLICATION:
--Make a time line showing the development of the various
types of plastics.
--Investigate local recycling efforts and what would be
involved is setting up a home and school plastics recycling
effort.
a. If your community has a plastics recycling system,
set up containers for holding the the plastic that
is to be collected and recycled. Investigate the
investment in collection and delivery time the class
will have to make to recycle the collected plastics.
b. If your community does not have a recycling system
for plastics, discuss the feasibility of setting up
a recycling system. Compare the the time and money
involved vs. the benefits to the community in energy
savings and waste reduction.
--Research the role of materials technology in our society.
Investigate the scientific principles behind the personal
and societal decisions that relate to technology.
--Investigate the properties and structure of the two main
types of plastics - thermoplastics and thermosets. Include
a list of products that are made from the various types of
plastics.