Walking Water
Materials Needed
 Food coloring
 400mL of water in total
 Three jars that are the same size
 Two sheets of Bounty paper towels
Procedure
1. Pour 200 mL into two jars
2. Make sure to leave one jar empty
3. Drop two to three drops of food coloring into the jars with water and stir it
4. Fold the paper towels vertically
5. Place one end of the paper towel in one of the jars with water; place one
end of the other paper towel into the other jar with water
6. For each of the paper towel, put the other end into the empty jar
7. Watch the colors “walk up” the paper towel and into the empty jar
Scientific Explanation
The water will “walk up” the paper towel and go into the empty cup as a result
of capillary action. The water travels in the gaps between the paper towels
because the adhesive forces (forces that lets water molecules to stick to other
substances) between the paper towel and the water are greater than the
cohesive forces (forces that lets water molecules to stick together) between the
water molecules. At the end, all three cups are equally filled with water.
Optional:
Next steps:
Use more than three jars to walk the water. Make sure to always leave one
empty.
Line up the jars with water and food coloring and put the empty jar at the very
end. Place the ends of the paper towels in each of the jars.
Suggested websites:
More on cohesion, adhesion, and other properties of water:
http://www.kidsdiscover.com/teacherresources/water-buoyancy-cohesionadhesion/
Helpful pictures and more about the Walking Water experiment:
http://www.coffeecupsandcrayons.com/walking-water-science-experimentkids/