Classroom Activities
History 101
To launch the unit in an engaging way, students will view Netflix’s History 101 Plastics episode. This documentary will provide a brief history of plastics and the various innovations and uses over the years. The information presented in the documentary does not focus much on the science of plastics, which leaves plenty of opportunity for inquiry. During the video, students will fill out a worksheet documenting the pros and cons of plastics, as well as the challenges mentioned in the video. After the video they will review with their table groups. Students will generate questions they have based on the information provided in the documentary. They will also document pros and cons to plastics, and they will identify plastic disposal as one of the main challenges. Students should be able to generate this information from watching the documentary, however the teacher can provide additional guided questions to research if necessary. This lesson is just an introduction to the rest of the unit, so it is not important for students to dive into the details behind plastic production and waste.
Polymer Models
To address the chemistry of plastics, students will perform two hands on activities. The first activity will be to create models of polymers using paper clips. Students will be introduced to the three types of polymer structures found in plastics: linear, branched, and crosslinked through a reading. Students will then use paper clips to model each type of structure. Students will analyze the structures to identify characteristics of the structures. The second activity will be a hands on lab creating two different types of putty. The lab experience will reinforce the different structural bonds and will allow students to create two different putties to compare different degrees of crosslinking in the polymers created. Students will document their observations of both types of putty and will be able to conclude that higher crosslinking results in a stronger structure.
Life Cycle
Students will be introduced to the concept of a product’s life cycle through a TED-Ed talk titled, “What really happens to the plastic you throw away”. The link to the video is found in the Teacher Resources section below. Students should be able to identify the various stages of the life cycle after watching the video. Students will then form groups and choose to research any of the stages more in depth and create presentations for the whole class. Depending on the grade level and comfortability with research, sources could be provided or student-generated. The research should be used as a way to show students the diverse environmental impacts of a product are not only in the disposal stage. While the rest of this unit is designed to address the end-of-life challenges associated with plastics, all stages offer opportunities for engineering and design. This type of analysis of a product’s life cycle can also be applied to any product.
Plastics Identification
Students will work in lab groups to investigate plastic samples. Students should be given six samples of unidentified plastic. The samples should include one sample of each: polyvinyl chlroride, polystyrene, polyethylene terephthalate, high density polyethylene, low density polyethylene, and polypropylene. Students will run tests on the various plastics to separate them by characteristics. The tests will inlude a density test in water, copper wire test, density in ispropyl alcohol test, reaction to acetone test, oil test and heat test. Students will test the various plastic samples and begin to sort them based on the results they get from the tests. Students will conclude there are different types of plastics with different characteristics.
Plastics Stations
To continue investigating plastics, students will participate in a stations activity. There are seven major plastics groups, and thus I create seven stations. One station for each type of plastic. I typically provide a couple different examples of each type of plastic for each station. You could also ask students and families to collect plastic items and have students sort them into the stations before doing the activity. Most plastics will have a number within the triangular recycle symbol. This is called the resin identification code. Plastics with a 1 would go to Station 1, those with a 2 go to Station 2, and so on. At each station I provide a key facts card that lists the scientific name, abbreviation, common uses, and recyclability. Students take notes at each station and also list characteristics they observe.
Engineering Bioplastics
Students will begin their engineering project for bio-based, biodegradable plastics by learning about the Engineering Design Cycle. Following the steps of the cycle, students will define the problem of petroleum based plastics and define the criteria and constraints for their bioplastic. For this unit, one non-negotiable criteria I will give to all students is that their plastic must be more degradable in comparison to petroleum plastics. In engineering teams, they will research current biodegradable plastics. Then, teams will have the opportunity to analzye the available materials. The materials they choose from are two different plasticizers, various starches, and various additives. Once they investigate the materials, they develop their own formula and mix all their chosen ingredients in a beaker on a hot plate. When ready, they pour their mixture into a mold and allow it to set. Students then observe their molds the next day. Based on the results, they may move into testing the bioplastic or they may revise their formula to create a new mold if their first try is unsuccessful. Once teams achieve a testable mold, students perform various tests depending on their chosen criteria and analyze the results of their testing. The tests should include degradability tests by burying the biodegradable plastics to see if they degrade over time compared to synthetic plastic. This may be analyzed over time to achieve usable data. Other tests can be performed before this test to make an initial conclusion and analysis of the bioplastic. Teachers may determine how many iterative designs they will allow students to run through depending on time and materials. The project concludes with a gallery walk of the different products from each team or class presentations. The format is selected by the students.
Adopt-A-Beach
As a culminating project for this unit, I will coordinate my class to participate in the Adopt-A-Beach proram. This is a program coordinated by the Alliance for the Great Lakes. I would organize a beach, date, and time for my students to travel to a local Chicago beach to participate in cleaning up the beach. As part of the clean up process, the Alliance asks students to collect litter and keep record of what is collected. The information is then entered by students into their database. The database is accessible for analysis of the historical data of each beach clean up, which can be used for further discussion around plastic pollution. In the classroom, students could also analyze their own data in more depth to determine the type of plastic they collect and the percentage of each type collected. They can then discuss the results to compare if their data matches what research has said about the manufacture and disposal of each type of plastic as well as what percentage is recyclable.
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