1.
Grades 7- 8
2. Overview The search for water has been recorded in the history of civilisation. Living things have always sought water for drinking and for other domestic chores. Without water, life can be unbearable. In modern times, many developing countries have included in their national plans, the supply of water which in some cases, have been very difficult. Water continues to be a needed commodity in life.
3. Purpose This lesson draws attention to the need to have water. The sources of water, purification and uses are to be discussed. The lesson emphasises the qualities of "pure" water.
4.
Objectives Students will be able to:
i. List the sources of water in their community
ii. Describe how water gets to their home
iii. Discuss the uses of water
iv. State the qualities of pure water.
5. Resources/materials
- Samples of water collected from different sources.
6. Activities and Procedures Water, a supposedly common commodity could be scarce in some communities. In some villages and towns in parts of Africa, potable water is difficult to come by. The result is that members of such communities resort to getting their water from all sorts of places:
- Pond ,stream or river
- Dug out well or bore hole
- Rain
- Pipe borne
- Sachet water sold as "pure water"
- Bottled water
The students should list the sources of water in their community.
Students who live in big cities may be familiar with potable water. The water they use flow from taps installed in their homes. Yet many of these students do not know what happens to the water before it gets to their homes. There is need therefore for the teacher to organise an excursion with the students to a town water works. Each city may have its own type of water purification system. But basically, the processes are very similar.
- Raw water is collected and filtered through large sand filters
- The filtered water is treated by adding a suitable germ killing substance such as chlorine
- The treated water is then stored in large tanks called reservoirs
- The treated water is then distributed to homes and factories through pipes laid underground from the water works.
The students should be made to describe their visit to a town water works. The Poem titled Our Pure Water should be read to the students.
Water is a very important commodity in many homes. The students should be asked to first discuss and then write about the uses of water in their homes and community. What are the constraints of water supply in their community and how do they think such constraints could be overcome. The term "pure water" has become common in many African countries. What indeed is meant by pure water? In many West African cities, water is now packaged and sold in sachets as "pure water". The health authorities have drawn attention to problems of these so called pure water as most do not meet the standard of pure water. So what is pure water? The scientific description of pure water should then be discussed with the students:
- Colourless
- Odourless
- Tasteless
- Free from germs.
Students should be made to assess not only the publicly sold pure water against the above criteria but also the water they use in their own homes. The dangers of drinking water that is not pure should be discussed.
7. Tying it all together Water is such an important commodity that the discussion should be interesting to the students. Supply of adequate water is a problem in many African countries. Why is it so? What in the opinion of the students, African countries should do to supply potable water to everyone.
8. Assessment Water from different sources should be examined. The students could place their own purity labels on water from different sources in their community.
9. Author(s) S. T. Bajah [email protected]
10. References Bajah, Sam. Tunde et al (1996) Integrated Science: A New Approach for Junior Secondary Schools. Book One [New Edition] Ibadan: University Press, Plc.
STAN (1998) Nigerian Integrated Science Project. Ibadan: Heinemann Educational Books (Nigeria) Limited.
Bajah, S. T. and Alice Eta Aim (1997). Science Poems for Children. Lagos: CSS Limited.