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Author(s): Nancy Moreno, PhD, and Barbara Tharp, MS.

Why Is Water Important?

Human beings are about 67% water. In fact, every living organism, whether composed of one cell or many millions of cells, contains water. Water is needed to transport nutrients and oxygen throughout living organisms and to carry out waste. Water also is vital for cooking, cleaning, growing crops, raising animals, transportation, production of electricity and manufacturing. Without water we would not only be unhealthy, we would not be alive. 


  1. Ask students, Why is water important? Have students devise and write down reasons why water is important in their science lab journals/notebooks. Tell students they may add to their lists as they complete the unit.

  2. Explain to students that they will complete a pre-assessment to see what they already know about water.

  3. Have students complete the pre-assessments individually; then collect and save the sheets. You should have students refer back to their pre-assessment answers at the conclusion of this unit to make any corrections based on the knowledge gained in the unit. This can be used as one component of the post-assessment activity (see Variations, PDF).

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932

Houston Endowment Inc.

Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education