Akron Global Polymer Academy Lesson Plans

Decomposition of Polymers: Removal of Chewing Gum

Grades: 9-12
Author: William E. Dunn
Source: An authentic assessment born of the need to solve a common problem. Removal of chewing gum from hair, clothing, or surfaces. This material is based upon work supported by the National Science Foundation under Grant No. EEC- 1542358.

Abstract

Our lives are fraught daily with things that gum up the works; especially chewing gum. If it happens to attach itself to your clothes, hair, or (heaven forbid) the inside of the family clothes dryer you have a real problem.

Objectives

What should students know as a result of this lesson?

• The student will learn the various types of chemical bonding reactions: synthesis; decomposition; single displacement; double displacement; and combustion. Also, how polymers are composed (polymerized)of monomers and decomposed (degraded) chemically and biologically. Solubility of solutes in solvents will be explored.

What should the students be able to do as a result of this lesson?

• The student will be able to remove chewing gum (polymers) from various surfaces and materials. As well as diagrams a visual image of the molecular structure and forces of which polymers are composed (polymerized) and decomposed.

Materials

Chewing gum polybutadine?, bubble gum, solvents, vinegar, mineral oil, clothes iron, metal spoons.

Procedures

Engagement

We have all chewed gum. Awaken with it entangled in our hair - on our face, clothes, and nose --in our pockets and in the dryer. As a nuisance, it ranks right up there with permanent marker graffiti, and fruit stained furniture.

Content Knowledge

Students should understand that polymers are long chained molecules made of many repeating units called monomers.

Students should understand that cross linking is a form of side chained bonding found in polymers chains.

Students should have basic lab skills. The chemicals and temperatures in this lab are generally safe, but students need to be able to work safely in lab.

Pre-assessment:

How do you remove chewing gum or bubble gum (Polyethylene); (Polyvinyl Acetate); (Polyisobutylene) from???

Before beginning any handling of materials, remind students to work safely and to use materials/equipment for the intended purposes.

Ask, "Which of the physical properties should we test?" Accept input. Lead them to identify the following in the procedures below: Also, conduct a discussion on how they will record their observations and tests. (Each student can test his/her own or groups can test several polymers (gums).)

For each polymer (gum) perform the following: Determine the density of your sample by placing the sample in water, (the first test solution) provided by your teacher. Record whether the sample sinks or floats in water and decide the approximate density. To find a more precise density for each sample, mass your sample, find the volume by water displacement, then divide mass by volume to calculate density. Compare your results with the tests performed by other groups.

Describe the polymer to include color, hardness, flexibility, opaque or transparent, odor, etc. and record your observations on the data sheet. Compare your results.

1. We will describe, weigh, and measure a stick of chewing or bubble gum to determine density.
2. Chew action (not in your mouth; but, by mixing with water, in a mortar with a pestle; or, in a cup with a spoon).
3. Blot dry, bag in zip-lock baggie, and weigh.
4. Attach pieces of gum to cloth patches by pressing with the back of a spoon.
5. Roll patches of cloth with gum attached and dissolve in test solutions of: 1). water; 2). glycerin; 3. Isopropyl alcohol; 4).warm (40 degrees Celsius) vinegar (3% acetic acid and 5). vinegar 6% acetic acid).
6. Attempt various methods (I-V) of removing gum from cloth patches.

Exploration

Assessment: Distinguish types of bonds: physical versus chemical bonds. Which of the method(s) worked best to break the bonds?

Students will work in small groups of 3-4 to explore which substance or methods (I-V) works best to remove chewing gum or bubble gum from cloth samples. Describe and draw the bonds on the molecular and atomic level.

Which procedure will work best to break the physical bonds?

1. Mechanical chemistry (mastical energy) chewed gum (shirred bonds) mimicked using a toothbrush to remove, versus.

Which procedure worked best to break the chemical bonds?

1. Chemical solvents (alcohol, glycerin, vinegar, water).
2. Thermal energy: Apply ice to gum on cloth and pull apart.
3. Thermal energy: (pressing gum and cloth between waxed paper with a flat-iron?) versus
4. Thermal chemical energy (warm vinegar).

Explanation

Students will be able to explain the processes of chemical bonding, physical bonding, and thermal reactions, on a macro and sub-microscopic (molecular) level.

Assessment: students can explain and demonstrate a mastery of vocabulary: chemical bonds; cross-linked; molecules; monomers; polymers; physical bonds; shirring forces; solvent; thermal energy. Also, how cross-linked bonds can be shirred or broken - by mechanical, thermal, or chemical means.

Elaboration

Students will be able to demonstrate by balancing equations and demonstrating how energy bonds are formed and broken.

An authentic assessment (lab) will show: how bonds are formed and broken; thus proving the laws of conservation of mass and conservation of energy.

Prerequisites

Students will need to understand : atomic structure; sub-atomic location, and charge. As well as, electron configurations.

Best Teaching Practices

• Hands on/Minds on Learning
• Real Life Situations and Problem Solving
• Inquiry Approaches

Alignment with Standards

NGSS Standards:

• HS- PS2-6 Communicate scientific and technical information about why the molecular-level structure is important in the function of designed materials
• HS- ETS1-2. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering

Common Core Standards:

• RST.9-10.3. Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text.
• WHST.9-10.2 Write informative/explanatory texts, including narration of historical events, scientific procedures/experiments, or technical processes.

Ohio Standards:

• SCIENCE INQUIRY AND APPLICATION - During the years of grades 9 through 12, all students must use the following scientific processes with appropriate laboratory safety techniques to construct their knowledge and understanding in all science content areas: Identify questions and concepts that guide scientific investigations; Design and conduct scientific investigations; Use technology and mathematics to improve investigations and communications; Formulate and revise explanations and models using logic and evidence (critical thinking); Recognize and analyze explanations and models; and Communicate and support a scientific argument.
• INTERMOLECULAR CHEMICAL BONDING - Compounds containing carbon are an important example of bonding, since carbon atoms can bond together and with other atoms, especially hydrogen, oxygen, nitrogen and sulfur, to form chains, rings and branching networks that are present in a variety of compounds, including synthetic polymers, fossil fuels and the large molecules essential to life.

Content Knowledge

Polymers are long chained molecules made of many repeating units called monomers

Cross linking is connecting polymer chains through side chained bonding.

Safety

• Caution should be used in working with latex as some students have allergic reactions to it. Students should wear non-latex gloves for this activity. Students should also use caution working with ethyl alcohol as it is flammable. Do not use open flames for this activity. Students should wear safety goggles for this activity. Appropriate lab safety protocols, including: goggles; aprons; gloves; and fume hoods.

Applications

Neither student-centered learning nor hands-on learning is as effective when children confront concepts that are not applicable to their own lives. This supports the idea that knowing a concept is being able to apply it; indeed, scientific information and its applications do become more meaningful when children can tie them to their real life experiences. Children engaged in authentic problem-based learning apply their science knowledge to questions they have about why things happen in their world, and they discuss the social ramifications that are often associated with scientific concepts.

Assessment

Assessments will be formatted to International Baccalaurate (IB), National, and State Common Core standards and Pro core assessments.

Other Considerations

Grouping Suggestions:

• Students will grouped in flexible groupings according to the assignment, skill levels, randomness and peer -tutoring arrangements.

Pacing/Suggested Time:

• Pacing will be according to the districts' adopted curriculum, and scope and sequencing. The Cambridge Physics Outlet, (CPO) sequencing is adopted to the "Foundations of Physical Science, with Earth and Space Science" by Thomas Hsu.

Printable PDF Worksheets

Labsheets will be from Investigations in the "Foundations of Physical Science, with Earth and Space Science" by Thomas Hsu.

Safety Disclaimer