Chalk Chromatography

Watch marker colors climb a chalk stick in minutes, then try it. Chalk, 3 markers, and water, plus the capillary action explained.

 

Materials you'll need

• White chalk
• Washable markers in different colors (we used pink, blue, and green)
• Shallow dish or tray
• Water

 

Step-by-step tutorial

Step 1: Get a stick of white chalk.

Step 2: Using your 3 washable markers, draw a band of color around the chalk for each one, leaving a white gap between colors.

Step 3: Fill a shallow dish with about ½ inch of water, then stand the chalk upright in the dish with the blank tip touching the water.

Step 4: Watch as the water climbs up the chalk over the next several minutes, picking up the colors and carrying them along. The once-sharp stripes will spread, blur, and blend together into a new pattern.

Learn more

This trick works thanks to capillary action — the same force that pulls water up into a paper towel. Chalk is full of tiny holes, and when you stand it in water, those holes pull the water upward, past gravity's pull. As the water climbs, it dissolves the water-soluble dye in your marker lines and carries it along, so your once-sharp stripes spread, blur, and blend into new shapes and colors where they meet.

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