Walking Water is one of the most stunning experiments to watch — coloured water literally walks from glass to glass along paper towels, mixing the primary colours into new ones as it goes. It demonstrates capillary action, the same force that lets giant trees drink water all the way up to their leaves. This guide adds extra exploration ideas to the classic experiment.

🧪 What You Need

  • 6 clear glasses (any size, but matching helps)
  • Water
  • Food colouring — red, yellow, and blue
  • 6 paper towels (folded into long strips)
  • A tray (in case of spills)
  • A notebook to record your observations

How to Set Up Walking Water — Extended Edition

  1. Line up 6 glasses — close enough together that a folded paper towel bridges between them.
  2. Fill alternate glasses with water — fill glasses 1, 3, and 5; leave 2, 4, and 6 empty.
  3. Add the primary colours — red in glass 1, yellow in glass 3, blue in glass 5. Stir well.
  4. Fold the paper towels into strips — about 3cm wide and long enough to dip into both glasses.
  5. Bridge the glasses — bend each paper towel into a U and place one end in a coloured glass and the other in the next empty one.
  6. Predict and record — before you start, draw the glasses in your notebook and write what you think will happen.
  7. Watch the rise — water will start climbing the paper towels within a few minutes.
  8. Check at 30, 60, and 90 minutes — draw what you see at each stage. The colours will mix in the empty glasses (red+yellow=orange, yellow+blue=green, red+blue=purple).

🔬 What's Happening? (The Science)

This is a beautiful demonstration of capillary action. Paper towels are full of microscopic spaces between their plant-fibre threads. Water clings strongly to itself (cohesion) AND to the paper fibres (adhesion). These two forces team up to pull water UP through the tiny spaces in the paper, against gravity, all the way over the bridge and down into the next glass. It's the SAME force that lets trees drink water all the way up to their leaves — even on a 100-metre-tall redwood. As the colours travel, the empty glasses receive water from both neighbouring coloured glasses, so the colours mix in the middle.

⚠️ Safety Tip: Adult supervision recommended. Food colouring stains — work on a tray. Don't drink the coloured water. Wash hands when finished.

🌟 Did You Know?

Capillary action also explains everyday things you've probably seen: paper towels soaking up spills, oil rising in a lamp wick, ink spreading across paper, even the way blood is collected in a tiny tube for a blood test. Anywhere a liquid travels through narrow spaces against gravity, capillary action is at work — and your kitchen experiment shows the very same force.

🎯 Try This: Become a Real Scientist

  1. Repeat the experiment but use only 3 glasses (one with water, one with paper towel bridge, one empty) — note how long the colour takes to walk across.
  2. Try DIFFERENT paper types: kitchen roll, tissue, printer paper, blotting paper. Which works best?
  3. Try warm water vs cold water — does temperature affect speed?
  4. Make a results table comparing each test — that's real scientific data!

📚 Sources & Further Reading

Written by Parikshet More (KidsFunLearnClub, Dubai) and reviewed for accuracy. Facts checked against the references above.