Coffee Filter Rainbow

Marker rainbow (1)

Coffee Filter Rainbow

Coffee Filter Rainbow 540 400 admin

How can one color be many colors? Ask your kids how many colors are hiding in other colors. My boys gave the usual answers, red and blue are in purple, blue and yellow in green. But when I asked what colors make black, they were stumped. With just two simple ingredients and water, find how many colors can hide in black.

What you need:

  • Coffee filter
  • Black marker

What you do:

  1. Fold the coffee filter in quarters.
  2. Color the tip of the coffee filter cone black.
  3. Dip the black tip into water and lay it flat on plate.
  4. Watch for the rainbow to creep up the filter!

Why it works?

The coffee filter spreads the water upwards and separates the different color particles in the black marker ink. The color black reflects no colors. By mixing lots of colors which absorb specific wavelengths and reflect others, the colors end up absorbing any wavelengths reflected by any one color, leaving only black.

Want a little more color excitement? Try different color markers on the tip or fold the coffee filter in different ways to make different patterns.