Subject: Earth Science
Learning Levels: Primary
Author: Randy Yerrick
Data gathering and observations will take place at the school site and also in the local community. A schedule of activities needs to be flexible to account for rain storms, field trips, and city administration meetings. This will provide the maximum impact for student products.
Make a map of your playground noting grassy areas and paved. Remembering that water flows downhill, try to guess where the water flows that falls on your playground during a rainstorm. Look for hints like hills, gutters, drains, erosion in the soil, and traces of the waters path. In teams have students identify water flow for different sections of the playground, drawing arrows on the map to denote the direction.
In this activity we will approximate how much water actually is captured by the ground and how much runs off. In the United States about half of the water used is drawn from groundwater sources. This water takes much time to seep deep into the soil. The deeper the groundwater source, the longer it takes to recharge. Shallow groundwater (100-500 m beneath the surface) can take up to 300 years to recharge while deep groundwater (>1000 m beneath the surface) can take over 4000 years!
Use your map of the playground to estimate how much playground land is either covered with buildings or pavement. Where does water go that strikes these surfaces? Consult your map from Part 1. It is likely that much of it flows into a drain or local sewer for capture and treatment. Use transparencies of large scale graph paper to compare the area that is paved to that which has grass or dirt. If your map is generated with a drawing program like Appleworks, make gridlines or assign colors to your different surfaces. Color and count the number of squares that makes up the area of paved surfaces and compare it to the total area of the playground. The amount of rain lost to run-off is equal to:
(Area of Pavement & Buildings)
____________________________ X 100% = % of rain lost to run off
(Area of entire playground)
How much rain actually hits the playground each rainfall, each year? The next time it rains collect water that is running out the drain pipe. Choose a building (preferably a small one with only a few drain pipes) and catch all the rain water that is flowing out each pipe for exactly one minute. Teams of students can be stationed at each pipe for timing and collection. Gallon jugs or 2L bottles can be used and recycled for this experiment. Be sure to find all the drain pipes and roof gutters so that no water escapes that hits the top of the building. Sometimes their openings need to be widened depending on the amount of rainfall. Other students can be given the task of calculating the area of the roof by dividing the building into rectangles. For example, the area of an "L" shaped building's roof would be divided into two triangles for simplicity.
Students can compute the area (LxW) of each part of the building's roof and add these areas together.
With these two measurements of amount of rainfall in a minute and the area it fell on, it is possible to compute how much rain fell in the area per minute. For example, if 30 gallons of water were collected in 1 minute by all the student teams and the building's roof was 600 square meters, then the rainfall rate would be:
30 gallons / minute
_________________ = 0.05 gallons per square meter every minute
600 square meters
This measurement can usually be generalized to the entire playground. The area of the roof is necessary to calculate how many gallons (or liters) of water are falling on the entire playground. Once you have calculate the rate of rainfall you can figure just how much water has been lost to run off from your estimation of Part 2.
What are the problems with run-off? Often times whatever is on the pavement gets washed directly into the sewer. If you have ever walked passed garbage in the parking lot or noticed fluid drops from a car you may not have thought that these can be washed directly into water drains and can collect in local water sources like ditches, ponds, or rivers.
Download a local map for your area and see if there are any rivers or creeks. If there are look for areas where roads, parking lots, or other paved areas come close or cross over these bodies of water. It is likely you will find drains dumping directly into the water body. Take a video camera with you gather some images of what you find at the site. Is there pollution on or around the paved area? Is there evidence that water drains directly from this paved area into the water? Are there dumpsters, oil stains, or pollution next to the drain? Is there evidence in the water that pollution has traveled through run off from the paved areas? Take video of the parking lot directly before and after a rain. Where did the garbage go?
Examine some of the effects of pollution and run off. One test that can be done is the simulation of the effect of oil on birds' eggs. Some motor oil into a small container. Add four hard boiled eggs to the cup so that the eggs are completely covered. Do not touch the oil but remove one egg after 5 minutes with a spoon. After wiping it clean on the outside, break it open and record your observations. Do the same for the other eggs 15, 30, and 60 minutes. Discuss with your classmates your observations. What effect would oil and other street run-off have on birds nesting next to the pond, ditch, or river? Generate ideas to simulate other contamination by oil remembering that birds, frogs, turtles, fish, mollusks, insects and plants all are affected by run-off pollution.
Compile an iMovie or web page which demonstrates your findings. Share your products with your school, community, and even the city planners. Plan on attending the next city council meeting to ask what can be done about the run off pollution problem you have discovered.
From your experiments and knowledge gained from your experience with the city council make a plan for your school yard. What places on your school ground could be changed to maximize water seeping into the ground? Invite a landscape architect to come and evaluate your plans and give you feedback on what is and is not reasonable for your area. Ask him/her what they would do to decrease the run off of water on your playground without.
There are many levels of cooperation required of students for this activity. Students must work well in teams to successfully complete their experiments on measuring and mapping. Students must also collaborate when designing their plans for the school or making their movies. For example, students may produce an iMovie that simulates a live news reporter uncovering a story.
These activities also engage and educate students in the processes of civil planning. Students learn to cooperate and influence local decisions about their community and ways to improve their school and local area while educating the larger public about choices made during civil planning.
Student maps of the school yard and water flow (Part 1) can be evaluated by actually spraying water on the area or making observations of flow directly after a storm. Students can also be evaluated on the basis of the accuracy of their individual experiments of water collection (Part 2 & 3) and also the effects of pollution on the environment (Part 4). Student group grades can be assigned for completed projects, letters produced, and presentations made to local pubic officials. Students in small groups can be responsible for different tasks (e.g.: time keeping, observations, reporting) and receive group grades for their contributions.
iMovie, digital camera, computer, age appropriate reference books, Appleworks (optional)
Other materials include: motor oil, eggs, water, spoons, and paper towel.
See also: Main
page for Pond iMovie | Pond
UOP #1 | Pond
UOP #2 | Pond
UOP #3 | Pond
For more information, please contact Randy Yerrick at firstname.lastname@example.org