Discussion

Ask your class, "Where does rain come from?" and "How does it get into the sky?"

Discuss the Water Cycle. You may wish to use the books: What makes it rain?, or Water: What it is, what it does. See bibliography

Experiment

Materials needed:
A clear garden garbage bag; A twist tie; Some soil; Water; A source of heat.

Method:
1) Fill the bottom of the bag with soil.
2) Pour water onto the soil.
3) Tie shut with a twist tie.
4) Apply heat: either put the bag in direct sunlight, or beside a heater. (Not so near that it will melt the plastic).
5) After a few hours, observe what has happened. Water has evaporated from the soil and has collected at the top of the bag.
6) Remove from heat and move to a cool place.
7) Observe after 1 hour. The water vapor has condensed into drops and may have dripped or run down the edges of the bag.

Conclusions:
What caused the water to evaporate?
What caused it to condense?
How does this experiment illustrate the Water Cycle?

Where can water be found?

The Saturated Zone: Make your own Aquifer

Prior to doing this demonstration you will need to discuss with your group where water can be found. They will likely be able to name lakes, rivers and kitchen taps as sources of water. Using resource books such as Water for the World by Franklyn Branley (or other books you have available in the school library), introduce the concept of ground water. Talk about how people who live in the country get their water from wells which are drilled into the aquifer.

To make an aquifer, you will need:
A clear plastic container filled with sand, or a mix of sand, rocks and gravel.
Ask the children: "How can we put water into a container that is already full?"
Pour water into the container until it is full.
Discuss how the water fills the cracks and gaps between the rocks and the grains of sand.

How do we use water as a resource?

Group Discussion:

Initiate a group discussion about water pollution by asking your class:
-What do we use water for?
-Could we manage to live without water?
-What is pollution? Where does it come from?
-How can we help to keep our water supplies clean?

Try this group problem solving activity:

Water Pollution Solution

Gather some leaves, grass, stones, paper scraps and some cooking oil.
Fill several basins half full of clean water.
Divide the class into groups so that each group has a basin.
Point out to the class that the water in the basins is clear and clean.
Instruct each group to choos which materials they will dump into their basins.
Add that material to basins.
Provide strainers, cheese cloth, loosely woven fabric. Each group must decide how they will try to remove the pollutants.
The goal is to remove as much of the pollutants as possible.

When the groups are finished, ask a spokesperson from each group to tell the class what their group dumped into the water, and how they attempted to clean the water. How successful were they at getting the water clean?

Were some materials harder to remove than others?

Is it better to prevent pollution or to clean up water that has already been polluted?

How do rocks change?

Erosion Experiments

Set up a sandbox or sand table environment in which you have made mountains of sand, clay and rocks.
Provide the children with sprinkling cans and small pitchers of water.

Ask the children to describe the shape and size of the mountains.

Provide measuring instruments (rulers and measuring tape or string). Ask the children to measure the height, width and circumference of each mound.

Record their observations and measurements.

Encourage the children to predict what changes will occur when water is poured on the different materials.

As the children pour water on the mound, ask "Which mounds are affected by water? Why?"

Compare their predictions to what actually happened.

Take new measurements of the mounds and record these on a chart.

Weathering Rocks

After the children have recieved information about the effects of heat, ice, wind and rain on rocks, you may wish to try these experiements.

1 - Place several kinds of small rocks on a hot plate for ten minutes or longer.
2 - Using tongs, pick up the rocks one at a time, and place them in a pan of ice water.
3 - Observe what happens.

Which types of rocks (sedimentary, igneous or metamorphic) reacted the most to temperature changes?

Make a volcano

   Volcanoes are mountain formations that form along cracks in the earth's crust. Hot liquid rock (magma), gas and steam come up through the cracks in the earth's crust. This boiling mixture erupts through vents in the volcano and spills out onto the earth's surface.

Materials needed:

-a large plastic cardboard box, top removed.
-a plastic beaker
damp sand
bicarbonate of soda
white vinegar
red food coloring or red tempera paint

Method:

1 - form a mountain of damp sand inside the box. Tip: make sure the sides of the box are deep enough to contain the runoff.
2 - Press the beaker into the centre of the mountain.
3 - Fill the beaker about half full of bicarbonate of soda.
4 - Color the vinegar with red paint or food coloring.
5 - When it is time for the eruption, pour the vinegar mixture into the beaker filled with bicarbonate of soda.
6 - Stand back!