Producing Plastic from Milk

Richard Moyer and Susan Everett
Type Category
Instructional Materials
Article , Experiment/Lab Activity , Lesson/Lesson Plan
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



This article describes an engineering design task that engages students in the creation of polymers.  The lesson follows the 5E format of Engage, Explore, Explain, Extend, and Evaluate. Students use the engineering design cycle to develop a polymer from milk and vinegar.  Students are challenged to produce the most plastic using the fewest resources. During the explore phase students will vary the amount of vinegar; in the evaluate phase, they will vary the temperature of the milk.  The article provides the lesson outline, student handout, and links to background information to be used by the instructor.

Intended Audience

Educator and learner
Educational Level
  • Grade 8
  • Grade 7
  • Grade 6
  • Middle School
Access Restrictions

Available by subscription - The right to view and/or download material, often for a set period of time, by way of a financial agreement between rights holders and authorized users.

Performance Expectations

MS-ETS1-3 Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.

Clarification Statement: none

Assessment Boundary: none

This resource appears to be designed to build towards this performance expectation, though the resource developer has not explicitly stated so.

Comments about Including the Performance Expectation
This lesson works well to give students a perspective on the role of a chemical engineer. In order to connect this lesson sequence to the students’ lives, it would be beneficial to find a real-life scenario where a limiting reactant in the process is crucial to helping a group of people. The challenge to create the greatest yield of plastic at the lowest cost gives a student the opportunity to figure out the solution while using a fairly simple set of materials and instructions. To best meet the performance expectation, the final data needs to be evaluated in several ways before students can determine the best design solution that is the most economical. To scaffold some students, the teacher should create organizers where students make specific comparisons and move the best to the next level, organized like a small sports bracket. The conclusion section could lead to a discussion where students brainstorm hidden costs to give them more data. This can help students understand how determining a “best” solution can be very complex.

MS-PS1-3 Gather and make sense of information to describe that synthetic materials come from natural resources and impact society.

Clarification Statement: Emphasis is on natural resources that undergo a chemical process to form the syntheic material. Examples of new materials could include new medicine, foods, and alternative fuels.

Assessment Boundary: Assessment is limited to qualitative information.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
The article lists this performance expectation in the introductory text. This lesson is a strong foundation for meeting this performance expectation, but this lesson alone will not meet all points of this performance expectation. The article gives some background information (and links to additional information) for the teacher to use to help students make sense of this performance expectation, but the activity never explicitly says how to incorporate the information into the lesson. The teacher could assign students to make initial models of how plastics are produced and then follow up to have students revise their model as their understanding and knowledge grows. It is suggested to add the use of student-level background information to the lesson, prior to the extend phase. The teacher can have a discussion about the information and lead them to a discussion about other variables that may change the yield of the plastic.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
The author uses the 5E model to outline the lesson plan and the student handout. The investigation is described well in the article and the student handout provides plenty of instruction to the students. Since the creation of casein needs a certain ratio of ingredients, it is best to give students guidance so the materials will not be wasted. The format of the handout should be more student-friendly. It is advisable to adapt the handout provided to make a less overwhelming handout students to use in each part of the activity. Leave spaces for data tables or open lines for student responses. To differentiate for some students, you may need to pre-draw the data tables so they can be sure to get all of the data that is needed. Include a space for the students to draw the monomer and polymer paperclip models that are described in the explain section of the article.

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
The data analysis method is outlined in the student handout as well as in the text of the article. It is advisable to create modified directions with scaffolded graphing template that has the axes labeled and a scale written out.

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
In the activity set forth, the students use information to model monomers and polymers. The use of the paperclip models to help students visualize is very important. Teachers should have students record diagrams of the models. The use of a computer simulation or a video to show how atoms rearrange to form new combinations of existing atoms can also be used to help students visualize the changes that are occurring on a microscopic scale. Use of the simulation should be scaffolded, or demonstrated, by the teacher to be sure that students understand the ratios shown in the simulation, since reactions are not always the same number of each atom but may show the same ratio.

Crosscutting Concepts

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
During the engage phase of the lesson, students are asked to brainstorm about items made of plastic as well as the properties that plastics have. At this point, teachers should discuss these ideas as well as the functions that plastics serve in light of their properties. Later on in the lesson sequence, teachers could bring those functions up and have the students discuss how the polymer structure of plastics contributes to the functions that make plastics useful. When the students are "making things" with the plastic, in the Extend phase, they could be asked how the structure of the plastic relates to the function they chose for it. The teacher should add a written prompt to have students discuss the structure and function of plastics in a summative assessment to the lesson sequence.

Resource Quality

  • Alignment to the Dimensions of the NGSS: This article outlines a well-aligned lesson where students use the engineering design cycle to develop plastic that best fits the criteria. The materials and methods used are middle school appropriate and the supplies are easily purchased. The three dimensions of NGSS do exist in the lesson but are not explicit to the students as outlined in the article. The teacher will need to make sure students explicitly build an understanding of the concept of chemical reactions as well as the crosscutting concept of structure and function. The handout provided needs a bit of revision to be sure students are engaging in all three dimensions as they proceed with the activity.

  • Instructional Supports: The article gives the fundamentals for a teacher to lead classes through this activity. There is a good foundation for a teacher to use as a handout, although more needs to be added to make sure the 3 dimensions are explicit. There are no ideas for scaffolding or differentiation provided by the author. Teachers would need to consider the scientific language used in any background information and the handout to be sure that new vocabulary is defined in context. Diagrams to accompany the directions may also be a helpful modification. Data analysis could be scaffolding with pre-made data tables and pre-drawn axes on graphs to help students collect and look at the data effectively. The article does mention the use of safety gear. Since this lesson uses food to make a non-edible material, teachers may want to discuss the pros and cons of these materials with students. In a school where families struggle to have food, this could be a sensitive issue.

  • Monitoring Student Progress: The activity has many points where teachers could formatively assess student understanding through verbally sharing, exit cards, or sticky note comments. The second investigation is to be used as a summative assessment. Additionally, the students could use the data from the activity and information from the resources to create a response in a Claim-Evidence-Reasoning (CER) format. This response would address a question such as, What are the conditions that produce the greatest amount of casein plastic? Alternatively, a teacher could create a scenario for the activity where the students are chemical engineers for Acme Plastic Company and are tasked with developing a natural polymer for a toy company. The teacher would need to assign costs for the variables and require a set quantity of polymer for the production of a toy. The final assessment could have the students write a letter to a toy company describing their findings and giving a cost for the amount of plastic that would be used in each toy. The student should make suggestions to the cost-effectiveness of the toy and use evidence from the investigation to support his/her claim.

  • Quality of Technological Interactivity: - none -