Water-Holding Capacity
Can sand hold water? Can clay? What difference would it make to soil if each were a significant component of soil soil?

You can conduct a simple water-holding experiment to find out.

Materials

scissors

1-liter plastic bottle elastic band cheesecloth or filter paper

measuring cup

masking tape

pitcher

stopwatch or clock with second hand

Procedures

1 With the scissors, cut off the bottom of a 1-liter plastic bottle so when inverted, it makes a funnel. Using an elastic band, securely fasten a piece of cheesecloth or filter paper across the bottle's mouth.

2 Place the funnel in the measuring cup. Place part of a sand sample in the funnel and use a piece of masking tape to mark the level it reaches in the funnel.

3 Fill the pitcher with a measured amount of water. Record the amount of water used. Pour the water into the funnel, noting the time when you start.

4 Note how long it takes the water to flow through the sand in the funnel into the measuring cup. Record this time.

Repeat with clay.

Based on this experiment, what do students think about the water-holding capacity of sand? Can sand retain enough moisture to support abundant plant life? If not, why do people use sand bags to stop flooding waters?

If the sand samples vary considerably from fine-grained to coarse-grained, you may want to perform the experiment on several different samples. Also, since you will repeat this identical procedure using soil samples from the study site, you should carefully record every step, including times and quantities.