Clean freshwater is another necessity of the human population. Although ¾ of the earth is covered with water, only a small amount is available as fresh water. The student may be or may become aware of the main way water prepares itself to be used by the human population. This method is called the water cycle. If you have the proper equipment, you can perform or have your students do a distillation investigation.
You will need a flask, colored water solution, heat source, distillation tube and a source of cold running water. Setup your distillation apparatus. Ask the student what they think will happen to the colored water solution. Perform the distillation.
Where and how does this type of activity take place on Earth? The student will probably say this occurs over the oceans continuously with the sun being the main source of energy. Why is the conservation of water important to the population? We live in a closed system and the amount of water on earth has remained constant but the demands have increased.
Water is called the "universal solvent" because it dissolves more things than any other single substance. Technology has come up with ways to make water safe to drink but at the same time, it has caused problems such as high construction and maintenance cost preventing underdeveloped countries to benefit from these advances.
Agriculture uses and wastes more water than any other single activity. Seepage, evaporation and run-off of water accomplish this. Municipalities add to this problem by building sewage treatment plants, dams and thermal pollution from industries.
You might make the student aware that water is not distributed evenly throughout the world. Developing countries are currently experiencing difficulty obtaining safe drinking water because of pollution and the scarcity of water. What are some ways we might help to alleviate this Problem?
The Investigating Groundwater: The Fruitvale Story would be a logical Module to use at this time as more than 1/5 of all Americans are dependent on groundwater that is contaminated by lead, toxic chemicals or fecal bacteria.
Conservation is one way to help reduce our use of freshwater. A fun way to make the student more aware of water usage is to have them do a home survey on how water is used in their home. This can be accomplished by having the student keep a record on the uses and amount of water used in their home. The Water Company can furnish a chart on the approximate amount of water used each time a various household task is performed. After completing this investigation, have the student suggest ways water usage in their home can be reduced.