Plastic Milk: You can make plastic from milk

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In this activity (on page 2 of the PDF), learners make a plastic protein polymer from milk. Adding vinegar to milk causes the protein casein to solidify or curdle. After allowing the casein to dry, learners can investigate its plastic properties. This activity is a great way to introduce learners to polymer chains, and how they form from individual molecules. Learners can imagine polymer formation by having individual learners link hands to form a line. This is one of three activities in the Take Home guide for the Industrial Chemistry unit in OMSI's Chemistry Lab. Also included in the PDF are: Chalk it up and Shrinkers.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
1 to 7 days

Estimated Materials Cost:
$1 - $5 per student

Age Range:
Ages 6 - 14

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per student)

  • ½ cup milk
  • ¼ cup vinegar
  • plastic tub (yogurt or margarine container)
  • old spoon or stick
  • paper towels
  • strainer
  • small plate


  • Engineering and Technology
    • Engineering
      • Chemical Engineering
  • Physical Sciences
    • Chemistry
      • Chemical Bonding
      • Solutions
    • Structure and Properties of Matter
      • Atomic Structure

Informal Categories

  • Food and Cooking


To use this activity, learners need to:

  • see
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access



Funding Source:

  • National Science Foundation