Fifth Grade NGSS
Water, Ecosystems, Human Impact

 

Exploring techniques to filter water.

 
FIFTH GRADE -FILTERING WATER

OBJECTIVES:

·         Analyzing why water cycle is a natural filtration.
·         Experimenting with filtration.

VOCABULARY:       

·         solvent
·         condensation
·        
evaporation
·         filtration
·         precipitation
·         water cycle

MATERIALS:
·         Giving Water a Second Chance by J. R.Blueford
·        
Funnels
·        
Beakers
·         Erlenmeyer flask
·        
Sand
·        
Water with soil mix
·        
Coffee filters

BACKGROUND:

Water is our most common natural resource.  It is essential to the biology and chemistry of all living things, it plays a major role in shaping the earth and is an active agent in many physical reactions. It is important to most life to keep it clean.

There is plenty of water on Earth, but 97% of this water is saline (contains dissolved salts).  Only 3% is fresh and about two thirds of that amount is locked up in polar ice caps and glaciers; about one third can be found as ground water, lakes, and in the atmosphere.

Water exists in three states of matter:  solid (ice), liquid (water), and gas (vapor) at normal conditions.  Water is a colorless, odorless, tasteless liquid with a melting point of 0° centigrade and a boiling point of 100° centigrade.  

Water can be easily cleaned through the water cycle.  When water evaporates in the gaseous phase, it leaves all the impurities behind.  Water can also be cleaned through other natural ways.  Humans have created ways in which they can also clean water without going through a natural water cycle.

PROCEDURE:  

 

1.      Discuss with students the following major points about water or the hydrologic cycle.  Draw the diagram of the water cycle.

A.   Water precipitates from clouds as rain, snow, sleet, or hail to the Earth’s surface.

B.   Depending on a number of factors such as soil type, slope, moisture conditions, and intensity of precipitation will either infiltrate into the ground or runoff into rivers and streams

C.   Virtually no water infiltrates through paved roads and parking lots, so almost all of it becomes   urban runoff.  Runoff from rivers, and streams is stored in large bodies of water such as lakes, estuaries, and oceans.

D.   Water is returned to the atmosphere evaporation from the surface of land or water bodies, or through plants by a process called transpiration.

E.   Clouds are formed by condensation of water vapor that evaporated from the land or oceans.               

 

2.      Hopefully this diagram should be familiar to students and they should be able to tell you about each of the components.  Ask them which are human-made portions of the water cycle? (Reservoir, dams and canals.)  Where does a spring get its water supply?  (Usually from the ground water percolating up.)  Where does water from the mountains wind up?  (The oceans.)  Which is the newest water? (Rain) Oldest? (Oceans.) 

3.      Read “Give Water a Second Chance”  so students can see how the water cycle has been cleaning water for eons of time, but now people can clean it also with different methods.

4.      Give students a beak with about 150 ml of water, mix in about 5 ml of “dirt” from the school ground.  Make dirty water.

5.      Use funnels and put in a coffee filter (show them how to put it in by getting a round filter and fold it inhalf and then in half again.  

6.      First have the student just pour water with the filter and see how much is “cleaned”

7.      Repeat the experiment but use about 1/3 of the funnel filled with small grained sand and make another dirty mixture.  

8.      Discuss with children which one cleaned the most and why.

 

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