Where is our Water?
To learn how fecal matter can get into water supplies
- Containers of various sizes, including two 2-liter soda bottles
- Measuring cup, preferably one that includes milliliters
This activity works best if you can locate an eyedropper and a measuring cup or other container that indicates milliliters.
Collect one or two 2-liter soda bottles and containers of various sizes, and fill the two soda bottles with water. Inform the assembled kids that one of the bottles represents all of the saltwater and freshwater in the world. Now slowly and carefully begin to pour the water into a container with milliliters marked on the sides. Ask the kids to tell you to stop once you have poured the amount that accurately reflects the proportion of the planet’s water that is fresh. (See below; the answer is roughly 60 milliliters.) When a kid calls out “stop,” write down who that is and the amount of water in the open container. Continue pouring until all the kids have called out a guess of the correct amount. Now reveal to them the kid whose answer came the closest. That kid is the winner. Pour the excess water in the container back into the 2-liter soda bottle until you have roughly 50–60 milliliters in the other container. This will enable the kids to see the ratio of saltwater and freshwater in the world.
- All the water in the world: one full two-liter bottle
- Oceans and other saline water (groundwater and inland seas): 1,940 milliliters
- All the freshwater in the world: 60 milliliters
Next, tell the kids that the water in one of the 2-liter bottles represents all the freshwater in the world. Prior to this, write labels as follows: “Ice caps, glaciers, and permanent ice”; “Groundwater”; “Soil moisture”; “Freshwater lakes”; “Atmosphere”; and “Rivers.” Turn the labels over so the kids cannot read them. Number each container. Parcel out the water into the other containers as follows (Use a measuring cup if available; otherwise, estimate amounts as closely as you can.):
- All the freshwater in the world: one full 2-liter bottle
- Ice caps, glaciers, permanent ice: 1,360 milliliters
- Groundwater: 600 milliliters
- Freshwater lakes: 5 milliliters
- Soil moisture: I milliliter
- Atmosphere: 1 milliliter
- Rivers: 1/10 milliliter (one drop)
Source: "How much water is there on, in, and above the Earth?" U.S. Geological Survey
Arrange the containers on a table with the labels hidden, and write the categories on a flip chart paper or chalkboard. Ask the kids to compare the amount of water in each and vote on which bottle matches each description. Mark how many votes each number gets. For example, “Groundwater” may have six votes for bottle #2, three votes for bottle #4, and one vote for bottle #6. Once the kids have finished voting, turn the labels over one by one. Ask the kids to tally up how many correct answers they had. (You can ask them to write down their answers on scraps of paper, or you can go by the honor system.)
- How much water is available to us for drinking and agriculture?
- From which places (rainwater, surface water, groundwater, deep groundwater, some glacial water)?
- Why do you think it’s important to keep this water clean, to use it wisely, and not to waste it?
This lesson plan is an activity from the Environmental Activities for Youth Clubs and Camps, a resource developed by the Peace Corps Office of Overseas Programming and Training (OPATS). It was contributed by Peace Corps/Paraguay, Peace Corps/Nicaragua, Peace Corps/Dominican Republic.