PART 5: Capillary Action

Before Class:

1) Prepare one set-up for each pair of students. Instructor can do all this preparation prior and have everything ready at each child's seat. See Figure 5.
or

2) give the basic materials and one set of instructions for each pair of partners and let them do the experiment and record the actions in their Documentation Journals. Your allotted time can dictate which to do.

Materials needed for capillary action from a glass of contaminated water.

a) Cut one strip of paper towel, 2 inches wide and about 5 inches long, one for each student

b) Secure a clear glass or a clear plastic cup. If the cup is short, the paper strip may not need to be 5 inches long.

c) Fill the glass (cup) 1/3 full with water.

d) And add several drops of red cake coloring. The red color in the water simulates the toxic chemicals that exist in the earth's water bodies or the soil.

e) Next, place one end of the paper strip just below the surface of the red water and hang the remainder of the strip over the rim of the glass.

f) Wait. While waiting, make a diagram of the glass of red water, the strip and the resulting action. Label all parts and explain what is happening.

As a Substitute
Students like to be engaged in classroom activities, but if time does not permit, the following demonstration can be used:

1) The night before class time, trim 2 large stalks of celery on both ends.

2) Place one stalk in a glass of water to which 4 or 5 drops of cake coloring has been added.

2) Place the other stalk in a glass containing the same amount of water but clear.

3) Set aside at room temperature overnight. See Figure 5b.

4) Carefully transfer to the class room with stalks still in their respective glasses.

5) Break both stalks about midway the length and explain the movement of the water. Was some of the toxic chemical removed from the water?

Questions:

Is this action similar to the transpiration taking place in the plastic covered plant?
Explain the similarities with your diagram.

Is the toxic chemical being taken from the water?

What part of this action is similar to the transpiration of the plant covered with the plastic?

Conclusions:

Observing the discoloration in the one that set in the red water overnight, explain why it is not obvious that the water traveled up hill in the stalk that set in the clear water over night. Water traveled up the second stalk in the same fashion but is not visible to the eye. This demo can be discussed in connection with the plastic covered plant in much the same way as the demo with the paper strips.