Investigating the Water Cycle: Using Plants to Study Evaporation
In this science activity, students investigate the water cycle by testing the water evaporated from leaves (transpiration). They investigate concepts of evaporation and the movement of water through the different states of the water cycle by various guided inquiry experiments. Students compare evaporation of trees in the shade and in the sun. Students are asked to diagram their results for the experiment in their lab notebooks. Students are also asked to develop a testable question related to and formulate a method to evaluate their results. During another investigation, with a spin of the spinner, students simulate the movement of water within the water cycle and track their results.
Objectives/Concepts for Water Cycle Activity:
1) Students will be able to describe the movement of water within the water cycle.
2) Students will be able to identify the states of water as it moves through the water cycle.
Objectives/Concepts for the evaporation activity:
1)Students will be able to explain the process of water evaporating (transpiring) from the plant.
2)Describe the importance of plants in the water cycle.
Context for Use
Resource Type: Activities:Field Activity, Classroom Activity
Special Interest: Field-Based Teaching and Learning
Grade Level: Intermediate (3-5)
Description and Teaching Materials
Pair students and give each student clear plastic bag with tie. Go outside and have partners put the bag over plants and tie. Make sure there are some duplicate plants, some in shade and others in sun. Record plant type and location. Go back inside and begin the observation sheet in the journal. Have students formulate a testable question related to the experiment.
Later in the day retrieve the bags and observe, discuss, and complete the method through results and conclusion.
Water Cycle Activity:
Students will need the water cycle spinners and their science journals. They will need to be put together with a spinner, or students may use a paper clip as the spinner and their pencil as the base for the spinner. Students should work in pairs to trace the journey a water droplet might make during it's journey. Spinners are designed specially to have students land on one area more than another, just like a real droplet would stay put in certain stages of the water cycle. (Refer to p.161 Project Wet curriculum for more information). Students should record the number of times the spinner lands in each area, which can be used for a class discussion on the water cycle. Students may also make a bar graph of the class results in the different stages of the water cycle.
Water Cycle Spinner (Microsoft Word 39kB Oct5 07)
Water Cycle Assessment (Microsoft Word 41kB Oct5 07)
NASA Water Cycle Diagram
Teaching Notes and Tips
A practical tip for the evaporation experiment is to limit how far students may go to place their bags on the plants. Also, it is important to tell students to not go too far into any woods that may have poisonous plants.