Equipment

  • Coffee filter
  • Water solvable markers, preferably dark colours
  • A glass

Instructions

  1. Draw dots or other patterns with the markers onto the coffee filter, about 2 cm from the bottom
  2. Fill a class with about 1 cm of water
  3. Place the coffee filter in the glass so that the colour is right above the water and pay attention to what happens
  4. Remove the filter once the colour has risen the desired amount. Are the new colours different from the original ones?
  5. Repeat with different patterns and colours

What happens?

This technique is called chromatography. The force that makes the water rise upwards through tiny tubes inside the coffee filter is called capillary action. Capillary action enables even tall trees to get water and essential nutrients delivered to their leaves far above the ground. There are slim tubes inside the tree stem, just like the coffee filter. Water can rise through these tubes and defy gravity because of its electric charges. A little magical, isn’t it?

Equipment Coffee filter Water solvable markers, preferably dark colours A glass Instructions Draw dots or other patterns with the markers onto the coffee filter, about 2 cm from the bottom Fill a class with about 1 cm of water Place the coffee filter in the glass so that the colour is right above the water….Click to read more