Warm-up: Thinking About Water
1. Begin this lesson by discussing with your class the importance of water in our lives and the special properties that it has. Ask questions such as:
a) Why is water called the “universal solvent”? (Water is the liquid that can dissolve the most amount of substances due to its unique chemical makeup: 2 positive hydrogen molecules and one negative oxygen molecule)3
b) How might this relate to water pollution? (Water dissolves and absorbs nearly every substance in comes into contact with, including chemicals, toxins and other forms of pollution. These and other materials are carried with the water wherever it flows.)
c) What other special properties does water have? (Neutral pH, found naturally as a liquid, solid and gas, high specific heat index, high surface tension, etc.)
d) What do we use water for? Where does our water come from and where does it go? (Water is used in everything, from drinking water to agriculture and producing energy. Water comes from the local watershed such as lakes, rivers, and groundwater, as well as rain, snowmelt, and other forms of precipitation. Those of us in the US with running water get it from water treatment plants. Our water often returns to these sources, but also drains into gutters, ditches, sidewalks, rivers, streams, the ground, etc. )
Activity One: Introduction to Rain Gardens
1. Pass out a copy of Reproducible #1- Rain Garden Diagram to each student, or project it up on the board to save paper.
2. Go through the diagram with students, explaining what a rain garden is and what it is used for. Use Reproducible #2- Notes for Teacher to make sure you are covering everything.
Activity Two: Brainstorming Rain Gardens
1. When you have finished introducing rain gardens, have students break into lab groups to discuss what they have learned. Pass out Reproducible #3- Rain Garden Lab and show them the materials they will use in the lab. Give them time as a group to look over the lab and start brainstorming ways that they will create their rain garden.
2. Homework Assignment (optional): Students should do additional research on rain gardens at home that night to help them move faster the next day. Mention that there will be a prize for whichever lab group creates the best rain garden.
Activity Three: Lab - Designing a Rain Garden
1. Set out supplies at each table or lab station, or have students collect all the materials they will need for their group (clay, sand, gravel, etc.).
2. Have students follow the directions in Reproducible #3- Rain Garden Lab to build and design their own model rain garden.
3. Walk around the room and encourage students to try a variety of different designs and to record what worked and what did not. Ask them to explain which design they think is the best and why.
4. When they are finished, have the students put their rain gardens on display at the front of the room. Take a pitcher of water and slowly pour some over each model, having students observe and record what happens for each model.
5. To conclude, go through each model with the class and discuss the strengths and weaknesses of each. What worked well? What didn’t? Have students decide which model they thought was the best (based upon how water flowed in each rain garden). Optional: reward the winning lab group with a prize.
Wrap Up: Journal and Discussion
1. Have students take a few minutes to write down what they learned from this lesson. Have them sketch the elements of the model rain gardens that were most effective. Also ask them to write down any questions that they still want answered about rain gardens. When they are finished, lead a discussion based upon what they wrote, and answer any questions that they still have. Connect rain gardens to the bigger picture of the water cycle and how doing something small in your backyard can make a big difference.
Extension: Take it Outside, Build a Rain Garden!
Now that your class understands how rain gardens work have them build one at school! Groups of students can research different aspects, such as the best place to build, the type of soil needed, and the type of plants that would work best considering native species and bioremediation. Check out the following website for detailed instructions on creating a rain garden: www.raingardens.org