Articles

Experiments

Trivia

Handbook

NCW Info
National Chemistry Week - Experiment - Hidden Colours

The Aim:

to find out what colours are hidden in different coloured inks

What you will need:

  • white paper towel
  • scissors
  • ruler
  • plastic drinking straw
  • small glass
  • different colours of watercolour markers
  • water

What to do:

  1. Cut a strip of paper towel that will be about 5 cm wide and about 3 cm longer than the height of the glass.

  2. Fold the top of the strip down about 3 cm from the top.

  3. Cut two slits. (See picture.)

  4. Unfold the strip and slip the straw through the slits.

  5. Place the straw across the top of the glass. The bottom of the paper should just touch the bottom of the glass.

  6. Lift the straw and make a coloured marker line about 3 cm from the bottom of the strip.

  7. Pour a little water into the glass and lower the paper strip into the water. The water level should be lower than the coloured marker line.

  8. After some time the colours will be seen to separate. Encourage class discussion.

[IMAGE OF HOW TO FOLD THE PAPER]

Back to What To Do

Each colour will be carried up by the water at a different rate. This process is called chromatography. It is used by scientists to discover the ingredients in a substance.

Also see the experiment Colour Mixing. Hidden Colours shows that some colours will separate into more than one component. Colour Mixing shows the separate colours and the effect produced by mixing them.

 logo