MnSTEP Teaching Activity Collection > MnSTEP Activities > Polymers & Plastics - Classification & Models

Polymers & Plastics - Classification & Models

Amy Fahey, Oak Crest Elementary - Belle Plaine, MN, based on unit of study from the Houghton Mifflin Science Series (2007) - Chapter Matter Changes pages E2-E29.
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Students will use their prior knowledge about changes of matter including physical and chemical changes from the Houghton Mifflin science curriculum. Students will be examining and categorizing various types of plastics (polymers) to identify where they are found in everyday life and how their chemical properties (molecules link together as a chain) allow them to have unique physical properties (various plastic types hard, soft, sticky, or malleable).

Learning Goals

This activity is designed for students to:

Classify plastic (polymers) versus non-polymers

Distinguish between types of plastics (polymers)

Make a model for a polymer

Apply the knowledge to their daily life (where & how they use plastic products / recycling - tie in from earlier unit of study - Houghton Mifflin series 2007)

Process skills used in the investigation include: observing, questioning, comparing, and classifying.

Key vocabulary (concepts):


Prior knowledge - atoms (Atoms combine to make molecules.), solid liquid gas (These are the states of matter that the students will review)

New knowledge - polymer (Molecules that are built as a long repeating chains.), malleable (plastics in which a change can be made to its shape.)

Context for Use

Grade level - 3-5: Groups of 2 or 4
Class size 24-30; Rural Public School Facility
Introductory Lesson of a Topic Study - 1-2 lessons (including Lecture/Vocabulary, Classification Activity, Model Building, and Assessment)

Materials: various types of plastic and non-plastic items

This activity is to build upon and enrich their prior knowledge of atoms and molecules as they relate to physical/chemical properties and changes.

Subject: Chemistry
Resource Type: Activities:Classroom Activity
Grade Level: Intermediate (3-5)

Description and Teaching Materials


Various plastic objects for sorting activity (fleece items, plastic spoons, plastic plates, remotes, toys)

Non-plastic objects for sorting activity (wooden items, wooden spoons, metal spoons, glass, ceramics)

Plastic examples from students homes (from various locations of the home - kitchen, bathroom, living room, bedroom, etc...)

Science notebook

Introductory Activity - Sorting Activity -

Begin the lesson with a review of the curriculum studied from the textbook (definition of atoms, molecules, physical properties, and chemical properties). Share with the class that they are going to study the chemical properties of plastics (polymers) and how they create unique physical properties for various types.

Hand the students a shopping bag full of items (included should be various types of plastic and non-plastic items - examples wooden or metal items). Ask small groups to sort the items into two groups based on characteristics they observe. Remind students to use their five senses with the exception of taste to classify items. When a few minutes have passed, stop the class to allow for discussion on how and whey they sorted the materials as they did. Hopefully students were able to sort the plastic and non-plastic items. Guide their classification by having them focus on what do they think the object was made of and sort the items by what they are made from. They should have groups that have plastics versus a group with non-plastics (woods / metals). Ask how they were sure the item was plastic (compare examples of hard plastics to malleable types), and if they have questions about various plastic types.

Discuss with the students their findings and journal in their notebooks about the two types of groups the found. Have them extend their thinking about plastics by focusing on what they found in that group. Did the plastics they find all have the same qualities, or are they different in texture and flexibility? The plastics should have been selected to have different qualities from each other; this should lead to further questions about the composition of plastic. Have students write down their questions about plastics and what they predict is happening with each different type. Let students know in a different lesson they will be observing a demonstration and making a specific hypothesis about what happens with polymer structure (plastics).

Polymer Pet -

Remind students of the study of atoms and basic molecules (how we made water molecules by linking together one oxygen atom and two hydrogen atoms together - students demonstrated by holding hands to make an example of a molecule). Now we are going to make a polymer using a similar model, but this time we are going to link together molecules to form a chain. Our human chain of linked molecules will create our polymer. (Another example would be to link paper clips or strips of paper to form a chain). Our polymer would continue linking molecules until there are no more molecules to link together. After the human demonstration the polymer could then be modeled by using the objects from the above sort. The plastics could be linked together by sitting them close to one another. At one end a drawing of a face could be attached to the beginning plastic item and a tail to the ending item. This chain of items could be the new classroom pet - the Polymer Pet. Students could name the pet and add plastic items daily. If the pet is too big to store in the room it could be placed in the hallway. Allowing others to see it in the hallway may help others to realize how many types of objects are considered polymers.

Plastics can be grouped into categories (4 examples may include: hard, soft, sticky, and malleable). As an assignment students can bring in plastics found at home to share as examples of these four categories. Their examples can be represented by 4 different polymer pets. When students bring in their objects they should try to place them in the correct polymer area and link it to the other items students or the teacher has brought in. Other variations of the pet could include polymers that can be recycled or ones that we use the most of to show others more about recycling or our everyday use of such items.

Culminating Activity -

To review what students have learned about polymers keep pets up as long as the study lasts (remember this activity is linked to a larger unit of study). One way to expand space for the pet would be to place it in the school hallways and ask other classes to add to the pet. Students could create simple posters to explain the pet at various places in the hallway.

A way to assess knowledge would be to have students make human links of basic molecules you have studied (such as water or oxygen) and then ask them to make a polymer.

To further the study students can be asked to bring in various plastics from certain rooms in their homes to demonstrate how plastics are used most everywhere in our lives.

Students could also research and write about ways these plastics could be reused or recycled. They could draw posters to display in the hallway helpful hints to reuse or recycle certain items used at school or home.

Web sites:

Jancie VanCleave's 204 Sticky, Gloppy, Wacky, & Wonderful Experiments. 2002 Jossey-Bass.

Houghton Mifflin Science 2007.

Lilly's Purple Plastic Purse by Kevin Henkes

Teaching Notes and Tips

This activity is meant to be taught as part of a larger study that would incorporate an experiment and website activities. Please look for those activities with polymers taught by other grade 3 teachers at Oak Crest Elementary (Gloria Brandt - Demonstration & Experiment with Polymers / Don Fraser - expansion & assessment activities) on the SERC website.


Students can be assessed in the follow ways:

Classification of plastics (polymers) versus non-plastics (small quiz)

Polymer pet (class participation)

Molecule / Polymer representations (students link together)

Posters about reusing or recycling plastics


3.1.A.1 - (Scientific World View) - Student will explore the use of science as a tool that can help investigate and answer questions about the environment.

References and Resources