Rainbow Climb: Colorful Capillary Action Experiment
Time needed: 30 minutes
Difficulty level: Easy
Age range: 6+ years
Adult supervision: Recommended for scissors handling
Difficulty level: Easy
Age range: 6+ years
Adult supervision: Recommended for scissors handling
What You'll Learn
This experiment demonstrates capillary action - how water can climb up through tiny spaces in materials. You'll create a beautiful rainbow pattern while learning about the same process that helps plants transport water from their roots to their leaves.
Materials Needed
Materials collected: 0/6
Paper towels
Colored markers (rainbow colors)
Two clear containers
Water
Scissors
Pencil or wooden dowel
Optional
Safety Notes
Adult supervision recommended for scissors use
Marker ink can stain clothes and surfaces
Keep water away from electronic devices
Step-by-Step Instructions
1
Cut a paper towel strip in half lengthwise
2
Draw blocks of rainbow colors along one long edge
Color both sides in the same pattern
Let the ink dry completely
3
Fill both containers with a small amount of water
4
Place each end of the paper towel strip in a container
Watch as the water climbs up, carrying the colors with it
Watch It In Action
Watch how the colors climb up the paper towel and create a beautiful rainbow pattern. The video demonstrates both the basic setup and alternative methods for displaying your rainbow.
The Science Behind It
Capillary action occurs when water molecules are more attracted to the paper towel fibers than to each other, causing the water to climb upward.
This same process helps plants transport water and nutrients from their roots up through their stems to their leaves.
As water moves up the paper towel, it carries the marker ink molecules with it, creating the rainbow pattern through a process called chromatography.
Common Questions
Why isn't my rainbow climbing up the paper towel?
Make sure your marker ink is completely dry before starting, and check that the colored edge is just touching the water. Some marker brands work better than others - water-based markers typically work best.
How long does it take for the rainbow to form?
The process typically takes about 15-20 minutes, though this can vary depending on the paper towel brand and room temperature.
Can I save my rainbow creation?
Yes! Once your rainbow is complete and the paper towel has dried, you can laminate it to create a unique bookmark or decoration.
Take It Further
- Try different brands of paper towels to see which works best
- Experiment with different marker colors and combinations
- Create an arched rainbow by draping the paper towel over a pencil between two containers
- Try using coffee filters instead of paper towels to see how the material affects the results
- Compare water-based markers with permanent markers to see the difference
Related Experiments
If you enjoyed this experiment, try these next:
- Color-Changing Flowers: Another experiment involving capillary action
- pH Indicators: Also involving amazing color changes
