Swirling Milk

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In this chemistry activity, learners prepare two petri dishes, one filled with water and one filled with milk. Using food coloring and soap, they discover that milk is an emulsion, a special mixture of fats and water, two items that are not very soluble. While the food color is initially not very soluble in milk, the soap reduces the surface tension and allows the color to swirl and mix. A simple experiment that entertains young learners, but easily extends to older learners. This activity is currently used in the Everyday Chemistry Unit in OMSI's Chemistry Lab. Cost estimates are per 100 learners.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
5 to 10 minutes

Estimated Materials Cost:
$1 - $5 per group of students

Age Range:
Ages 4 - 18

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per group of students)

  • Two 25-ml graduated cylinders
  • Two plastic Petri dishes
  • Two small dropper bottles of food coloring.
  • Two 250-ml squeeze bottles
  • Whole milk, keep 1 gallon on hand
  • Concentrated dish-washing soap (keep 8 oz on hand)
  • Food coloring (red, yellow, blue, green)
  • One 600 ml beaker
  • One small jar with lid with hole drilled in lid
  • Toothpicks, keep 100 on hand
  • Small plastic beaker
  • Medium plastic beaker


  • Physical Sciences
    • Chemistry
      • Chemistry of Life
      • Solutions
    • States of Matter
      • Liquids

Informal Categories

  • Food and Cooking
  • Science Festivals Activity


To use this activity, learners need to:

  • see
  • see color
  • read
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Components that are part of this resource:

This resource is part of:

Access Rights:

  • Free access



Funding Source:

  • National Science Foundation