Activities

 Class Participation - Evaporation

Objective

To show that some water is initially captured by soil and that, over time, it evaporates back into the atmosphere.

Materials Needed

• Two paper cups for each student
• Scales
• Enough soil to fill one cup for each student
• Measuring cup or graduated cylinder

Procedure

Fill each cup with soil to within 1/2 inch (13 mm) of the top. Weight the filled cup and record the weight.

Poke small holes in the bottom of the filled cup to allow water to run through.

Gently pour two cups of water over the soil surface while a partner holds a second cup beneath the filled one to capture the water that runs through.

Weigh the filled cup and record this wet weight. Weigh and record on three successive days.

Questions for Discussion

How does this laboratory situation compare to the actual situation of rain falling on the ground?

What happened to the water held by the soil initially?

What is likely to happen to it now that is has evaporated?

How does water get into the atmosphere from plants?

 Class Discussion - Water, the Resource

Objective

To start students thinking about water as a limited resource and considering their role in water conservation.

What are some of the ways we use water each day in our homes?

What are other ways in which we use water?

How can we as individuals help in the effort to conserve water?

 Class Participation - Comparison of Family Water Uses

Objective

To make students more aware of the large amounts of water used in individual households.

Materials Needed

• Graph paper
• Pencil

Procedure

Have each student record the amount of water used in their home over the period of a school day. This figure can be obtained by reading the home water meter first thing on two consecutive mornings or by estimating toilet flushes (5 gallons or 20 litres), showers (35 gallons or 130 litres), washing clothes (40 gallons or 150 litres), and using the dishwasher (10 gallons or 40 litres).

Ask students to graph the water use of all the families.

Questions for Discussion

Was there a lot of variation in water use among families?

Did most families fall within the average use of 80-100 gallons (300-380 litres) per person per day?

Did some families use either a lot less or a lot more than the average?

What are some possible reasons for using either more or less?

What are some ways that water consumption could be cut?

 Demonstration - The Water Cycle

Objective

To show that the water we use is the same water that has been in use since the beginning of time. To demonstrate that an element that enters the water cycle remains in the system.

Materials Needed

• Clear plastic box with clear lid
• Heat lamp
• Plastic bag of ice
• Food coloring

Procedure

Prop the box at a 30 degree angle.

Pour 3.5 ounces (100 ml) of water in the box.

Replace the lid.

Focus the heat lamp on the lower portion of the box to create evaporation.

Secure the ice at the top of the box at the opposite end to create condensation.

Once the cycle of evaporation, condensation, and precipitation is established, add food coloring to the water in the box.

Questions for Discussion

What process is recreated by turning on the heat lamp?

What process is recreated by applying ice to the water vapor that collects in the lid of the box?

What principle does the addition of the food coloring demonstrate?

Does this mean that rain is pure?

 Demonstration - Percolation

Objective

To demonstrate that water percolates through soils with different grain sizes at different rates

Materials Needed

• Five plastic columns, 40 inches (100 cm) long and 2 inches (5 cm) in diameter
• Five gauze pads and rubber bands
• Five beakers to catch the water that percolates through each column
• Samples of clay, course sand, fine sand, gravel, and topsoil or 5 graduated sizes of plastic beads, approximately 2 measuring cups of each
• Measuring cup
• Stopwatch

Procedure

Secure a gauze pad to the bottom of each column with a rubber band.

Place a different soil sample or size of bead in each column until the column is approximately half full. Make sure all columns are filled to the same level.

Pour 3.5 ounces (100 ml) of water through the columns, one by one.

Time the passage of the water through each column.

Measure the amount of water that passes through each column.

If using soil samples, note the color of the water in the collection beaker.

Questions for Discussion

Did the water go through all of the columns at the same rate?

If not, why not?

Describe the relationship between the rate at which water passes through the soil and the size of its grains.

 Class Participation - Snow Density

Objective

To show that snow is comprised of water and air and that the density of the snow affects the amount of water produced when snow melts

Materials Needed

• Two small cans of the same size, one opened on both ends

Procedure

Measure and record the height of the can as the depth of the snow.

Push the can that is open on both ends down through the snow until the can is full of snow.

Carefully pull the can up to keep any of the snow from falling out.

Place the can over the opening of the other can and tape them together so all the melting snow falls into the lower can.

After the snow has melted, dip the ruler into the water and measure and record the depth.

Questions for Discussion

What is the relationship between the amount of snow collected and the amount of water produced?

How is the density of the snow calculated?

What are some of the factors that affect the density of snow?

Would the snow density be the same at the top and bottom of a deep snowpack?