Activity: Capillary Action
Ideal Group Size
Small to mid-size (up to
30)
Theme: Water
Grade Level
2-6
Set Up/Clean Up Time
10 minutes /10
minutes
Activity Time
10-15 minutes
Math/science questions addressed: What is capillary action? Can soap change the properties of
water?
Overview: Participants observe water moving up different types of paper in a process called
capillary action.
Materials: 3 aluminum pans, brown paper towel, 5 pair of scissors, 5 rulers, construction
paper, white paper, tape, pencils, 5 plastic bowls
Setup: There are enough materials for up to 5 groups. Compile sets of materials for each
group, consisting of: ½ of a brown paper towel, 1 scissors, 1 ruler, 1 strip of construction
paper, 1 strip of white paper, 1 tape, 1 pencil, 1 plastic bowl. Cutting strips: using the
provided construction paper pieces as a model, you can either have participants cut the strips
of white paper or do it ahead of time. Each aluminum pan needs about ½ inch of water and the
plastic bowls can be filled approximately halfway.
Activity 1:
To do:
1. Divide participants into 5 groups. Give each group ½ of a paper towel and have them cut
it into 5 strips the short way (like the construction paper, about 3” x 1.5”).
2. Each participant can take one of the paper towel strips and hold just one end of the strip
in the water in the plastic bowl. They should then observe the water begin to move up
the paper on its own.
Ask: What do you notice about the water and how it interacts with the paper towel?
Explain: Water molecules like to stick to things like paper and each other. As the water
molecules try to stick to dry paper molecules, they pull the other water molecules up with
them. This upward movement of water on the paper is caused by “capillary action.”
Activity 2:
To do: Introduce the setup that participants will be using for their next test by showing them
the aluminum pans and rulers (see photo on back of page).
1. Have each group make a prediction about which type of paper will allow the water to
travel up the farthest.
2. Each group will then tape 1 strip of white paper, 1 strip of paper towel and 1 strip of
construction paper to a ruler.
3. When they are ready, have each group lay their ruler over top of one of the aluminum
pans and observe what happens.
Ask: Why do you think one kind of paper is better than another at promoting capillary action?
Activity extension: If you also did the surface tension activities, what do they think would be
the effect of adding soap to the water? Would the water travel higher or lower? If there is time,
and inclination, try it!
These 2014 Summer Learning science activities were developed by Pacific Science Center