There are five processes by which water moves through the cycle:

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1 The Water Cycle Purpose To create a student-sized example of the water cycle in action. This activity may be performed in sections, but requires a significant time commitment (seed germination). It is best performed when worked into a curriculum plan. All of the water on Earth goes through a cycle in which the water changes its location or physical state through different processes. In accordance with the law of conservation of matter, water is not created or destroyed by this cycle: it just changes its form. Water can be found in all three states of matter during the cycle: solid (ice caps), liquid (lakes), and gaseous (water vapour). There are five processes by which water moves through the cycle: 1. Water in oceans and lakes evaporates into the air. 2. Cool air in the atmosphere causes the water vapour in the air to condense into a cloud. 3. Precipitation from the cloud falls to the ground as rain, sleet or snow, depending on the air temperature and atmospheric conditions. 4. The water on the ground percolates throughout the soil and some of it is absorbed by plants. 5. As plants go through photosynthesis (converting water, sunlight and carbon dioxide to form their own food), they absorb water from the soil and release some of it back into the air through transpiration. These patterns of change can vary, but the cycle occurs continuously. Water has been cycling by means of these processes since the beginning of time. Materials Three 2 litre pop bottles (with caps) Crayon or marker to mark plastic bottles Scissors String Empty film canister

2 Procedure 1. Remove the labels from the bottles. 2. Draw a line with marker or crayon just below the shoulder of bottle A, as indicated in the diagram (right), keeping the line at the same height on the bottle all the way around. 3. Using the same method outlined in (2.), cut bottles B and C just above the hips, as indicated in the diagram (right). 4. Poke a hole in one bottle cap using an awl or a pin. The hole should be just large enough to thread your string through it. Place this cap on bottle B. 5. Cut a 40 cm length of string. Fold the string in half and insert the folded end through the cap hole to make a loop inside. Leave at least 5 cm of each end of the string hanging down from the cap. 6. Place a cap with no hole on bottle C. Tie 20 cm of string around the bottle neck, so that one end hangs down about 7 cm. 7. Assemble the bottle column: B inserts into A; C inserts into B. These three parts of your model will be referred to as chambers for the rest of the activity.

3 Create a Bottle Environment 1. Wet both strings thoroughly. Add 150 ml of water to Chamber A. This will be the water source for the cycle. 2. Fill Chamber B with enough moist soil to cover the loop of string (about 200 ml will do). The string should run up into the soil, and not be pressed against the side of the column (the students will not be able to see the string running through the soil). 3. Plant several fast-growing, hardy plant seeds in the soil around the sides of Chamber B. While the seeds are germinating, leave Chamber C off - this will help with air circulation and help the seeds grow. 4. Place the film canister (or another bottle cap if you don t have a film canister) on top of the soil at the centre of Chamber B so that the wick tied to Chamber C hangs into it. If the film can will not fit between Chamber C and the soil, trim it with scissors. This is your rain collector. 5. Once your plants have germinated... Place Chamber C back on Chamber B and fill C with ice water. 6. The students are ready to draw the water cycle column and to begin filling in their observation sheets. Your finished water cycle column should look like this diagram:

4 64 Observation Sheet Indicate what the following parts of the water cycle column represent: a) The water and ice in Chamber C: b) The film canister in Chamber B: c) The water in Chamber A: How are the following processes demonstrated in your water cycle column? a) Evaporation: b) Transpiration: c) Condensation: d) Precipitation: e) Percolation:

5 Experiments How is your water cycle affected when: a) you add acid (vinegar) to the water in Chamber A? Does water in other parts of the cycle become acidic? Hypothesis: Results: b) you add acid to the soil in Chamber B? Does water in other parts of the cycle become acidic? Hypothesis: Results: c) Draw and label a diagram of the water cycle chamber