STEM Activity for Kids – Capillary Action

Capillary Action Activity



This is defined as the process of movement of liquid (like water) along the surface a solid (like paper towel). The liquid travels in the upward direction, which is against the direction of gravity. The tiny fibers in the paper towel act as capillary tubes which helps to pull the water in upward direction from the bottom. This is because the water molecules attach themselves to the tissue fibers.

Let’s due this science experiment and check it out ourselves.


  1. Place 3 glasses side by side on the table/floor.
  2. Fill 2 side glasses with 2/3rd water and keep the middle glass empty.
  3. Ask your child to add a few drops of red food colour in one glass and a few drops of yellow in the other glass filled with water.
  4. Now take two paper towels and place them half and half in the glasses (as shown in the image).
  5. Ask your child to now sit and observe what happens patiently. Slowly the coloured water will start moving up the paper towels.
  6. Wait for approximately 20 to 30 minutes for the magic to happen.
  7. Ask your child, “What do you see?”
  8. Now, ask her/him to observe how the coloured water from their respective glasses will flow into the empty glass.
  9. The child should be able to see that the empty glass is getting filled with water.
  10. Point at the middle glass and ask your child “What colour do you see in this glass?” The child will notice orange colour water in the middle glass.
  11. Now explain your child what Capillary action is (refer to the top).
  12. Enjoy experimenting with different colours. You may also create a rainbow through the same process.

What will your kid learn?

  • Understand the science behind capillary action
  • Colour mixing

About the instructors

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Capillary action

Materials Required

  • 3 glasses
  • 2 paper towels
  • Any 2 colour water colours (Red, Yellow)

It’s beautiful to see kids learning. And they learn more while playing. And that’s our vision “Learn while you play”.

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