Investigating Plastic Polymers: Building a Model and Relating to Real Life Connections

This activity is designed for students to:

• Make a model for a polymer
• Develop a hypothesis and take part in a controlled scientific experiment
• Compare data and draw conclusions based on the experiment
• Apply the knowledge to their daily life

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

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 (The students will try to change its shape)

Grade level - 3-5: Groups of 2 or 4
Class size 24-30; Rural Public School Facility
Unit Project - 5-6 lessons (including Lecture/Vocabulary, Classification Activity, Model Building, Experimentation, Application, and Assessment)

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

Materials

Various plastic and non-plastic objects for sorting activity
Plastic examples from students homes
Plastic Ziploc bags
Sharpened round pencils
Water
Balloon
Containers to catch water in
Computer lab/internet access
Science notebook

Introductory Activity - Sorting Activity

Build onto knowledge of atoms/molecules and physical properties with study of polymers
Examine objects
Sort into two groups based on observations (plastics/polymers and non-plastics)
Discuss how grouped and observations (these items are plastics or polymers vs. non-plastics)

Polymer Pet

Gather objects from the sorting activity above and share how they are going to become a polymer pet. Remind students of the study of atoms and basic molecules, and now molecules are going to link together to form a chain; that chain will create our polymer pet. (Another example would be to link student hands, paper clips, or strips of paper to form a chain). Our polymer pet would be created by linking molecules together; these linked molecules have unique physical properties due to their structure. We will examine their structure more in the upcoming demonstration and experiment.

Other variation - Plastics can be grouped into categories (4 examples may include: hard, soft, sticky, and malleable) and 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.

Experiment & Demonstration

Review with students about the polymer pets and how their chain-like structure stays connected, yet can be moved by other objects. Demonstrate with the magnetic version of polymer pet on the board. Share with the students how we are going to investigate the properties of polymers with a balloon and air & a plastic bag full of water and a pencil.

• Show balloon with air and ask what would happen if I placed a pencil through it? (It would burst)
• Then hold up a plastic bag full of water and ask the same question
• Have students try placing pencils through a bag of water (or ask a volunteer)
• Then complete a basic O/K/W/H/L chart (guiding them through the observations, knowledge, want to know sections
• Allow students to hypothesize about other things they could try on the plastic bag (to test polymer structure) - examples: place more pencils through bag, different positions, different objects, amount of water, different bag types
• Regroup to discuss hypotheses tested and what they learned
• If possible use a ball of yarn to show how yarn can be pierced by a pencil and the fibers remained gathered together around the pencil.

Culminating Activity

Direct students to the web site game to practice their knowledge of polymers and how to apply them to real world settings. When the students have finished the game, they will explore objects used in the game and discuss. For assessment have students take the quiz at the end and record their scores.

Web sites
www.americanchemistry.com/s_plastics/hop_jr/activities
http://web.archive.org/web/20111215045930/http://www.stevespanglerscience.com/experiment/00000049


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

Houghton Mifflin Science 2007.

Lilly's Purple Plastic Purse by Kevin Henkes

Students need to be reminded that this is a hands-on scientific investigation and that appropriate behavior and handling of materials (especially water) is expected. Also note that when puncturing the bag the pencil should enter and exit the bag in one straight motion. The plastic bag does not leak when the pencil is pushed through it. Removal of the pencil shows that the hole left by the pencil appears stretched around the edges (not torn) and is slightly smaller in diameter than that of the pencil.

Students can be assessed in the follow ways:

• Science journal (observations, questions, hypothesis, data, and response to hypothesis)
• Polymer pet
• Online assessment test

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.

3.1.B.1 (Scientific Inquiry) Students will ask questions about the natural world that can be investigated scientifically.