Water, Water Everywhere

Keywords: water cycle, hydrology, precipitation, surface water, runoff, infiltrate, groundwater, aquifer, transpiration, evaporation, elevation, watershed; Lesson Plan Grade Level: sixth through eighth grade; Total Time Required for Lesson: two 40- to 45-minute class periods; Setting: classroom

Goals for the Lesson

  • Students will recognize that there is a lot of water on the Earth, but not much of it can be used for our drinking water and other water supply needs.
  • Students will recognize that ground water and surface water is a very small percentage of the Earth's water.
  • Students will gain an understanding of how much water is used on a daily basis in a household setting.
  • Students will develop an understanding of how important it is that we take care of our water resources.
  • Students will identify ways to conserve water.

Materials Needed

State Standards Addressed: E & E Standards: Watersheds and Wetlands (4.1); Renewable and Nonrenewable Resources (4.2); Ecosystems and their Interactions (4.6); Humans and the Environment (4.8)

Teaching Model: The 5-E Instructional Model (Engage, Explore, Explain, Elaborate, Evaluate)

Subjects Covered: earth science, ecology

Topics: water availability, water usage, water conservation

Preparation

  1. Ask the class what they know about how much water there is in and on the earth. Note their responses on the board to be able to make comparisons with info obtained from handouts.
  2. Distribute handout "How Much Water Is There on (and in) the Earth?"
  3. After the first paragraph is read, distribute the following handouts to elaborate upon the terms presented:
  4. After reading the handout "How Much Water Is There on (and in) the Earth?" distribute the handouts about glaciers and icecaps:
  5. The handouts already distributed give statistics regarding the amount and distribution of water on Earth. To help students get a better concept of water amount and distribution, conduct the following activity.

Activity (adapted from "All the Water in the World" from www.epa.gov ) (Original activity developed by Paul Susca, New Hampshire Dept. of Environmental Services.)

  1. Present to the class a 5-gallon aquarium filled with water. Explain that the water in the aquarium represents all the water in the world.
  2. List on the board the following types of water supplies on Earth:
    • oceans
    • groundwater
    • rivers
    • icecaps/glaciers
    • freshwater lakes
    • inland seas/salt lakes
    • atmosphere
  3. Using a measuring cup, remove 18 ounces of water from the aquarium.
  4. Color the remaining water in the aquarium green with food coloring. This water remaining in the aquarium represents the proportionate amount of water that is in our oceans. The 18 ounces is proportionate to water that is not ocean water.
  5. Pour 15 ounces of the 18 ounces into an ice cube tray. This represents that amount of water that is held in glaciers and icecaps. This water is not readily available for our use.
  6. Since the 13 ounces of water in the ice cube tray is comparable to the amount of water in an ice pack, place the ice pack in the aquarium to represent the total amount of water held in glaciers and icecaps.
  7. The remaining 3 ounces represents the world's available fresh water. Of this amount, only a fraction of an ounce (approximately one dropper full) is held in the world's fresh water lakes and rivers. Place a dropper full of water in a small cup or in a student's hand.
  8. The remaining water (approximately 2.5 ounces) is ground water. Pour this remaining water into a cup of sand. Explain that ground water is held in the pore spaces of soil and fractures of bedrock.
  9. Distribute activity handout, "All the Water in the World" (Appendix B).
  10. After computing the answers for the handout, ask the students if they are surprised to know that such a small percentage of the water in the world is fresh.

Questions for Follow Up

  1. Why isn't all fresh water usable? Some is not easy to get to: it may be frozen or trapped in unyielding soils and bedrock fractures. Some water is too polluted to use.
  2. Why do we need to take care of surface water/ground water? Water is very important for humans, plants/crops, and animals. If we waste or pollute it, we may find that there is less and less of it available for us to use.

Conclusion

  1. To make students mindful of the amount of water used in one day's time, distribute handout, "How Much Water Do You Use?" (Appendix C) to each student.
  2. Divide the class into groups of three. As homework, assign each group to work cooperatively using the handout to calculate how much water is used during a typical day.
  3. The following day, compare and discuss the findings of the different groups.
  4. Compile a master chart of water usage by calculating the average numbers from all the groups.
  5. Discuss the implications of using so much water.
  6. Assign the groups to come up with a list of at least 10 ways to conserve water on a daily basis.

Assessment

  • Assess students' learning by having them write in their journals summarizing what they have learned about the amount and distribution of water on Earth. In addition, have students explain why they think they should conserve water and have them list 7 specific ways they can do so.

Extension

  1. Distribute "Pennsylvania Water Facts" (Appendix D).
  2. Use information from the lesson on "Reading and Understanding Topographic Maps" along with the information from this lesson as an introduction for a lesson on reading local topographic maps and identifying local watershed.

References

U.S. Geological Services' Web site

Evironmental Protection Agency Web site

Drohan, Joy, William Sharpe, and Sanford Smith (2002). Incredible Water with the Water Lion . University Park, Pa.: Center for Watershed Stewardship, The Pennsylvania State University.

Swistock, Bryan, and Sanford Smith. (2001). From the Woods: Watersheds . University Park, Pa.: The Pennsylvania State University.

Drohan, Joy, and Charles Abdalla (2000). Valuing Pennsylvania's Water Resources . University Park, Pa.: The Pennsylvania State University.

FRIT course handouts provided by Brian Swistock, extension associate, Water Resources & Forest Hydrology, Penn State Department of Ecosystem Science and Management.

Author

George Ness, BLaST IU17; LaSaQuik Alternative Education Program