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Video Lessons

Chemical Reactions: What is Plastic Made From?

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Summary

Grade Range
6th-8th
Group Size
2-3 students
Active Time
65-75 minutes
Total Time
2 days (drying time for casein plastic)
Area of Science
Chemistry
Key Concepts
Chemical reaction, polymerization, plastic, properties of matter
Credits
Svenja Lohner, PhD, Science Buddies Alumni
Video narration by Jennifer E Paz
Pricing
Free for a limited time thanks to individual donors
Video Lesson
Get Student Link

Overview

Chemical reactions can result in interesting products! In this lesson, students learn how plastics are made by conducting a polymerization reaction in a simple milk-to-plastic transforming experiment. During their experiments, students will be able to compare the physical properties of their reactants (milk and vinegar) and their resulting organic casein polymer.

Learning Objectives

Materials

For teacher preparations:

Per group:

Per student:

Prep Work

  • Print out a worksheet for each student.
  • Heat all the milk you need for your class (1 cup per student group) in a pan on a stovetop or burner until the milk is steaming. Alternatively, you can microwave the milk in a microwaveable container by warming it at 50% power (two minutes at a time) and watching it to make sure it does not overflow. The milk will be steaming when it is sufficiently hot.
  • Store the steaming hot milk in a thermos until it is needed. It should stay warm enough for at least two hours.
  • Prepare a materials station for students. Place the measuring cup, the thermos with the hot milk, and a bottle of distilled vinegar at the station so that students can measure out these materials during class. Optional: if you decide to use decorative materials such as small cookie cutters, food coloring, and/or markers, place these at the materials station as well.
  • For the explore part of the lesson, provide the students with a work surface that can get damp.

Engage (10-15 minutes)

In this video, students find out how plastic was invented and discuss the omnipresence of plastics in today's world. They learn what plastics looks like on a molecular level and are introduced to polymerization reactions.

Explore (40 minutes + 1-2 days of drying time)

This video explores the central question, "What is plastic made from?" by guiding students through an activity that lets them create casein plastic from milk. During their experiment, students will observe how a chemical reaction, such as a polymerization reaction, creates a new substance that has different properties from those of its reactants.

Reflect (15-20 minutes)

This video summarizes for students everything that they have learned about plastics and polymerizaton reactions. It also asks students to think about the positive and negative impacts of plastic on the world.

NGSS Alignment

This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:
  • MS-PS1-2. Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
  • MS-PS1-3. Gather and make sense of information to describe that synthetic materials come from natural resources and impact society.
This lesson focuses on these aspects of NGSS Three Dimensional Learning:

Science & Engineering Practices
Asking Questions and Defining Problems. Ask questions that arise from careful observation of phenomena, models, or unexpected results, to clarify and/or seek additional information.

Constructing Explanations and Designing Solutions. Apply scientific ideas, principles, and/or evidence to construct, revise and/or use an explanation for real-world phenomena, examples, or events.
Disciplinary Core Ideas
PS1.A: Structure and Properties of Matter. Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it.

PS1.B: Chemical Reactions. Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.
Crosscutting Concepts
Structure and Function. Structures can be designed to serve particular functions by taking into account properties of different materials, and how materials can be shaped and used.

Connections to Engineering, Technology and Applications of Science

Influence of Science, Engineering and Technology on Society and the Natural World. The uses of technologies and any limitation on their use are driven by individual or societal needs, desires, and values; by the findings of scientific research; and by differences in such factors as climate, natural resources, and economic conditions. Thus technology use varies from region to region and over time.

Assess

The student worksheet can be used to evaluate students' understanding of the activity and basic concepts. A quiz is available as a summative assessment.

Extensions

Activities

Milk Curdling with Enzymes!
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STEM Activity
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43 reviews
Have you ever gone to pour yourself a cup of milk, and all you get is clumps? What happened to the milk is called coagulation, which is the mechanism that occurs when proteins in the milk clump together. While you do not necessarily want this in your milk, without coagulation (or curdling), there would be no cheese or yogurt, which is why it is a very important process in the food industry. Wonder how you can make milk curdle? Do this activity to find out! Read more
Making Everyday Objects Out of Mushrooms: Environmentally Friendly Design
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STEM Activity
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10 reviews
Maybe you have grown vegetables or flowers, but have you ever grown the flowerpot? Yes, you read that right! In this activity, you will use mushroom roots to grow a biodegradable material that can be molded into a product of your liking, like a flowerpot! Growing a set of bowls, a lampshade, or a pot is easier than you might think. Once you try it out, you just might feel inspired to replace some of your plastic objects with ecological counterparts that you created from mushroom roots! Read more

Lesson Plans

Turn Milk into Plastic!
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Lesson Plan Grade: 6th-8th
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33 reviews
Teach your students how to make plastic out of milk in this hands-on lesson plan! You will conduct a simple milk-transforming experiment to explore how plastics can be derived from a natural resource such as milk. Students will perform their own experiments and can even create a product from their resulting organic casein polymer. Read more
NGSS Performance Expectations:
  • MS-PS1-2. Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
  • MS-PS1-3. Gather and make sense of information to describe that synthetic materials come from natural resources and impact society.
Sustainability: How Our Actions Affect the Environment
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Lesson Plan Grade: 5th
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6 reviews
How do our everyday actions contribute to our ecological footprint? Can we change our individual actions to be more environmentally friendly and create a more sustainable lifestyle? In this lesson, students will evaluate their own environmental impact using an online tool called Your Plan, Your Planet, and evaluate simple ways to reduce their ecological footprint as an individual or community. Read more
NGSS Performance Expectations:
  • 5-ESS3-1. Obtain and combine information about ways individual communities use science ideas to protect the Earth's resources and environment.
Sustainability: Reduce Your Environmental Impact!
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Lesson Plan Grade: 6th-8th
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Global warming, pollution, and deforestation are just a few examples of how human actions affect our planet. How can we reduce our impact on the environment? In this lesson, students will find out by using an online tool called Your Plan, Your Planet. Based on their findings, students will come up with their own action plans aimed at reducing their personal ecological footprint and assess its effectiveness after implementation. Read more
NGSS Performance Expectations:
  • MS-ESS3-3. Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.

Blog

Teach Chemical Reactions - 20+ Chemistry Lessons and Activities
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Blog Post
Use these free chemistry lesson plans, experiments, and activities to teach and explore chemical reactions with K-12 students. A chemical reaction occurs when two or more substances (reactants) are mixed together and result in one or more new substances (products). When teaching about chemical reactions, educators show chemical reactions in action and, when possible, let students get hands-on exploring reactions. With classroom science experiments,… Read more

Careers

Chemist
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Career Profile
Chemists use their knowledge about chemicals to discover new ways to make better products and materials. A chemist might try to optimize the production of casein plastic by varying the amounts of vinegar added to the milk or changing the reaction temperature. In fact, chemical research has led to the development of thousands of new and improved synthetic materials such as plastics and other products like the fibers in your clothing. Read more
Materials Scientist and Engineer
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Career Profile
Material scientists apply chemistry, as well as physics, to study all aspects of materials. They might study the properties of the resulting casein plastic to test its strength, density, or water resistance. This way, they can help to develop new products or improve existing ones. Material science involves working with both natural as well as synthetic materials that are used in a wide range of products and structures. Read more
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