Where's the Water?
To identify the reservoirs of the Earth's water cycle (e.g., oceans, ice caps/glaciers, atmosphere, lakes, rivers, ground water) locally and globally and to graph or chart relative amounts in global reservoirs.
In this lesson, students will explore and identify Earth's reservoirs and bodies of water locally or globally, learning how water is distributed around the world. Using 10 liters of water to represent all the water on Earth, students will divide this water according to the percentages given for different water bodies.
See discussion questions for some general background information as well as leading questions to help guide discussions.
The lesson is designed in three parts:
- A classroom activity that helps students visualize the relative volume of usable water on Earth;
- follow up STEM activities where students apply their knowledge of Earth's water resources;
- and watershed connections.
1. Show the students a map of the world or the globe. Ask them what the color blue
represents (water). Ask them what percentage of the globe/earth is covered in water (72%). Is it all usable by humans? (No)
2. Ask the students to identify the various reservoirs of water on the earth other
than oceans. As they give answers, make a list in the front of the room. Use the
following categories for student responses: icecaps/ glaciers, groundwater, freshwater
lakes, inland seas / salt lakes, atmosphere, and rivers. Note: Students will have
many ideas. For this exercise freshwater lakes would include ponds, reservoirs and
wetlands; groundwater would include wells; and rivers would include springs, canals,
and small streams.
3. When the list on the board is complete, pass out the water distribution worksheet and divide the students into groups.
4. Ask the students to estimate the percentage of water in each reservoir. Based on their estimation, have them calculate the volume of each reservoir, and record their data on the water distribution worksheet.
5. Discuss the results of the groups' estimations. Where did they think most of the water was located?
6. After discussing the initial estimations, demonstrate to the class the actual amounts found in each reservoir (table included in background information). As you mention each reservoir measure out the actual volume and add it to your small container.
7. Show the small container to the students and ask if all this water is actually available for human use (answer is no). Discuss each reservoir and remove the volumes not available for human use. See discussion question 1 for more details. This can lead to a discussion on water conservation and protection from pollution. See discussion questions 2 and 3.*This activity adapted from Activity D-1: Sources of Drinking Water in the manual Water Conservation and Nonpoint Source Pollution by Dr. Kitt Farrell-Poe.
1. Have students create pie charts of water reservoirs on Earth. A second pie chart could be created to show the AVAILABLE water reservoirs on earth to compare and contrast with the first. You can view examples of graphed data here.
2. Have students explore the actual percentages of different reservoirs that are impacted by pollution.
3. Have students research water availability and use in your home state. See USGS Water Science Center website for state by state information: http://water.usgs.gov/district_chief.html
Curriculum and Teacher Materials
Core Alignments By Grade: