4) Rainbow Science

Can you stack different liquids into a rainbow of layers without letting them mix? All you need is a steady hand! 

What you need

  • Tall cup
  • Food colouring (red, blue, and yellow) 
  • Honey
  • Dish soap 
  • Cooking oil 
  • Rubbing alcohol
  • Water* 
  • Measuring cups**
  • Stirrer** 
*Not provided
**Use measuring cups provided in the Colour Mixing Challenge 

Step by step

1. Drop 1 drop of red and 1 drop of blue food colouring into the honey and mix evenly with the stirrer. 

2. Slowly pour the purple honey mixture into the tall cup without letting the mixture touch the sides of the cup. 

3. Add the blue dish soap to the tall cup. 

4. Fill 50ml of water in the measuring cup. Add in 1 drop of blue and 1 drop of yellow food colouring. Mix evenly with the stirrer.

5. Carefully pour the green water into the tall cup. 

6. Wait for the 3 layers of liquids to settle - Honey, Dish Soap, and Water. 

7. Measure 50ml of cooking oil with the measuring cup (Keep the remaining of the cooking oil for the 'Rainbow Rain' activity). Tilt the clear jar and pour in the cooking oil very slowly. 

8. Add 1 drop of red food colouring to the rubbing alcohol and mix evenly with the stirrer. Gently pour the red liquid into the tall cup. 

9. Your liquid rainbow is complete! 

  • Observe how the different colours are separated in the bottle. 
  • What sequence are the colours in? 
  • Why do you think they are able to be separated that way, and not be mixed together? 


Important Tip: 

When pouring the liquids in to the clear jar (with the exception of honey), be sure to tilt the jar so that the liquid runs down the side of the jar slowly so that the colours will not mix.  



    What you need

    • Tall cup** 
    • Measuring cups** 
    • Stirrer**
    • Food colouring** (Red, Blue, and Yellow) 
    • Cooking oil* 
    *Not provided
    **Items provided in the previous Colour Mixing Challenge Activity


    Step by step

    1. Pour 40ml of cooking oil into a measuring cup . 

    2. Add in the red, blue, and yellow food colouring (5 drops each), and mix evenly with the stirrer. 

    3. Using another measuring cup, measure 300ml of water and pour it into the tall cup. 

    4. Slowly pour the cooking oil mixture into the tall cup. 

    5. Wait for 10 seconds. Do not blink! It will soon start to rain in the cup!