Milk rainbow experiment | Fizzics Education


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Create a Milk Rainbow

Create a Milk Rainbow

Follow FizzicsEd 150 Science Experiments:

You will need:

  • Full-cream cow’s milk
  • Food Colouring
  • Dishwashing detergent
  • A saucer


Milk rainbow science experiment - ingredients needed

Pour some milk into a saucer (ignoring your cat: this is for the cause of science).


Drop four different colour drops of food colouring near the edge of the saucer.


In the centre, add one drop of dishwashing detergent.

4 Milk rainbow science experiment - colours swirling on a plate

… and watch the result!

5 Pouring a dirty water mixture in a clear plastic cup into another clear plastic cup that has a simple paper filter across its top (held in place by a rubber band)

Get the Unit of Work on Mixtures here!

  • How can we separate mixtures?
  • What are the different techniques?
  • From chromatography to magnetism, join us to explore the variety of ways we can separate mixtures!

Includes cross-curricular teaching ideas, student quizzes, a sample marking rubric, scope & sequences & more

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6 Gross slime
7 Teacher showing how to do an experiment outside to a group of kids.

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– Help students learn how science really works

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Why Does This Happen:

The drop of detergent reduces the surface tension of the milk at the same point where it dissolves the fat molecules in the milk. The higher surface tension of the surrounding milk pulls the surface of the milk away from this spot dragging the food dye with it.

The food dye begins to swirl as the detergent breaks down the fats within the milk, and as the fats break down the water carries the food dye to where the fats used to be filling the newly available space.

Variables to test

More on variables here

  • Try different types of milk. Do they all work?
  • Does the temperature of the milk matter?

A man with a glove above a liquid nitrogen vapour cloud

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