Water Cycle - Water (1)
Post Lab

  • Exploring components of water.
  • Discovering how water is used by humans.
  • hydrogen
  • oxygen
  • water

Students use a worksheet to learn about ways to  clean water.


Filtering System in Northern California

Water is a chemical combination of hydrogen and oxygen.  Water is a colorless, odorless, and  tasteless substance.  Point out hydrogen and oxygen on the periodic chart.  Ask the children if they know what hydrogen is.   The element hydrogen is a gas.  Ask the students if they know what oxygen is.  The element oxygen is a gas.  Water, therefore, is a combination of two gases that form an entirely different substance and state of matter!

Water is very important to our everyday lives.  Emphasize to your students, because they are so familiar with water, that they take it for granted.  You may want to interject some environmental concerns that
clean water is important for humans and most organisms to survive.

Water is an important commodity to all organisms that live on Earth.  Although it appears as if we will never run out of water, only 3% of all of the Earth's water is fresh (2/3 is locked up as ice, 1/3 as groundwater, lakes, and atmosphere), 97% is salt water which is unusable by most land organisms' metabolic systems. 

Humans demand clean water. In  some areas there are more people than clean water.  Methods to clean used water are becoming more widespread.  The end product is referred to as “recycled water.”  Instead of nature cleaning the water, humans have created factories that accelerate cleaning the water.  They use filtration, chemical additions, disinfection, and microorganisms to clean water. The term “recycled water” implies that water has been cleaned naturally or by methods developed by people to reclaim water.  

Water can be recycled for billions of years.  Once water is formed on Earth, it has the ability to change forms easily.  If water becomes dirty or polluted when it is a liquid, it can clean itself through evaporation process, form a cloud, and then come back as clean rain water.

  1. Show students hydrogen and oxygen on the periodic table of the elements. (they are circled in the diagram to the right)  Discuss that both are gases, and when they join to make a compound it is a liquid at normal temperatures.   

    Use the online interactive version of the periodic table if you want to go over the different elements. 
  2. Discuss the importance of clean water for every organism on Earth.  Bring out that water can be cleaned by nature and also cleaned by humans through different methods.

  3. Read the online book called, "Giving Water a Second Chance," by J. R. Blueford. This book goes through the different stages of how water is cleaned both naturally and by human developed methods.
  4. Use the worksheet as a coloring exercise to facilitate a discussion on what happens to water that has been used in the past and how it is cleaned.  For instance the dinosaur is drinking water, but as all organisms, it must come out.  The dinosaurs will go to the bathroom, but nature will naturally filter the liquid through different rocks and soil.  It  will clean the water so it can be used again.  This is nature's way of recycling water.  

  [Back to Water Cycle Grid]  [Back to Water (1)]