Background:
This is a water quality unit. It is designed for a second grade class. Most children are not aware of how much water there is on the surface of the planet. This unit will help the students understand and realize that most of the planet's surface is water and how little is available to use. They will also learn what they can do to use water resources wisely.

Objective:
Students will be able to determine that the Earth is made of seventy percent water.
Students will be able to explain the water cycle.
Students will be able to determine the causes of pollution in the water and will know what they can do to help.

Materials:
globe activity sheets hand lenses crayons scissors water-tap, pond. aquarium, swimming pool 20 one quart containers

Activities:
Day One:

1. The students discuss things they find on the earth. The students are in groups of four. Each group has a globe to view. Brainstorm to make a list of everything they suggest on the chalk board.
2. Distribute the water and land worksheet. Cross off all of the items on the chalk board that the students named that are also on the activity sheet.
3. Count all of the items that are on land and the items that are in water.
4. The students color the land green and the water blue.
5. To further help them realize the large amount of water on Earth, have the students cover the portion of land with one hand. They will easily be able to cover this area.
6. Next have them try to cover the water portion with one hand. They must determine how many hands it takes to cover the water portion of this sheet.

Day Two:

1. Pose the following question to the students: " How do we get all this water on Earth?" Also ask " how do you think the water gets into the sky?"
2. Explain that the Earth has a special system called the water cycle, which keeps water moving in a circle. Water falls from the clouds in the sky. It comes in the form of rain, snow, sleet, or hail. This water reaches the earth. Water can also be a gas. To do this it must evaporate. Once the water evaporates, it then returns to the clouds. Soon it will return to the earth as water-rain, snow, sleet, or hail. The cycle starts over again and continues. The water cycle is endless.
3. Draw a simple sketch to illustrate this on the board.
4. The students draw the water cycle at their desk. The students create the water cycle booklet that is attached.

Day Three:

1. Discuss where does water go.
2. Explain that water that goes underground is called groundwater. Sometimes groundwater can become polluted.
3. Further explain that some people drink groundwater.
4. Ask them what they think happens if people drink polluted water.
5. Write their ideas on the board. The students complete the great ground water activity sheet.

Day Four:

1. Discuss with the students that sometimes people cause water pollution. Note that most people don't realize that they are polluting.
2. The students complete the polluted water activity sheet. First the students match the cause of pollution to the effect it has on the environment.
3. Discuss each picture and the effect it causes.
4. Each group has a sample of lake water, tap water, aquarium water, ground water, and water from a swimming pool. The students make observations. They discuss the differences in color smell, texture, note floating and non-floating objects, and any other observations.
5. The students graph and chart their findings.

Day Five:
A field trip to the water pumping station and the water reclamation district is the culminating activity. They will see how the water cycle works, how water comes into their homes and how it is cleaned and purified for use.