Water Purification

Wilson, Wardell                       Raster School
                                      737-1010
                      

Objectives:
Participants will develop an understanding and appreciation of water 
purification techniques and their implications for health maintenance.
Upon completion of the activities students will:
   .  explain how polluted water can be a source of disease
   .  illustrate how a lack of oxygen in water can kill fish
   .  interpret and explain the water cycle
   .  express ways of purifying water for drinking purposes
   .  differentiate ways in which the body uses water

Apparatus and Materials:
Various water samples - tap water, distilled water, well water, 
mineral water, carbonated water, reverse osmosis water, five day old
pond water; glass slide, microscope, candle.  ( Activity 1.0 )
Charcoal placed in large funnel followed with gravel and then sand,
flask, paper napkins for filter.              ( Activity 2.0)
Two jars filled with tap water colored with methylene blue, dried 
grass placed in one jar.  Close jars tightly with screw tops and set
for five days, litmus paper.                  ( Activity 3.0 )
Decomposition reaction jars with electrode tops, Reverse Osmosis Myron 
Meter.                                        ( Activity 4.0 ) 
Reverse Osmosis Water Purifier and a Carbon Block Filtering Water 
Purifier.                                     ( Activity 5.0 ) 

Recommended Strategy:
This P/A (Phenomenological Approach) lesson is based on the IDEAL 
Problem Solving Method utilizing the following steps:
     I - Identify the problem (What are you asked to do here?)
     D - Define the problem   (What are the parts?  How related?)
     E - Explore the possibilities (Interpret and analyze problem)
     A - Act upon the possibilities (Plan and follow a strategy)
     L - Look for results (Explain results from the strategy)

Vocabulary:
Sediments, desalination, aeration chlorination, toxicity, acid rain, 
ionized, water borne disease, typhoid, cholera, carcinogens, 
chloroform, carbon tetrachloride, trihalemethanes, acid rain, 
suspended solids, dissolved minerals, precipitate, dialysis, 
respiration, cell oxidation, excretory organs, conductivity apparatus, 
oncology. 

P / A
Nationwide newspaper reports, magazine articles, and network T.V. 
specials frequently focus on drinking water pollution and its impact 
on health.  EPA scientists point out that over 700 chemicals have been 
found in America's drinking water and over 34 states have serious 
drinking water pollution problems.  One way of coping with this 
problematic situation is to identify how water becomes polluted and 
understand how it can be purified by various methods. 
     Activity  1.0  Observe drops of water from pond water jar on slide 
under microscope. Write and illustrate on paper what you have 
identified and observed. 
     Activity  2.0  Pour remainder of pond water into filtration set up. 
Funnel and catch in flask.  Record observation, then observe drops of 
flask water under microscope.  (Activity 2.1)  Add aluminum sulfate to 
the flask and watch for a sticky jelly like substance - aluminum 
hydroxide - Observe substance and then observe drop under microscope. 
Shake and then filter through napkin into another beaker. Examine this 
water and residue and record what you found. 
     Activity  3.0  Observe the two jars prepared earlier - Jar A and 
Jar B - with the same amount of tap water with blue coloration, and dry 
grass in Jar A. Discuss observation.  Use litmus paper to test for pH 
in both jars. Note results. 
     Activity  4.0  Illustrate the water cycle and compare it to the 
process of distillation of water.  Define hard and soft water.  Explain 
how boiling of water removes carbonate ions and the deposit collects in 
tea kettles and steam irons.  Have students picture in their minds that 
frozen distilled water, frozen rain water, winter icicles are generally 
very clear and un-cloudy whereas frozen tap water is unclear. Have 
students observe and try to explain. ...NOTE...  Pure water is neutral, 
it has equal numbers of hydronium and hydroxide ions.  As water becomes 
ionized with acids or bases, it moves from the pH #7 position of 
neutral yellow and the water becomes less pure, this degree of impurity 
is reflected in the cloudy ice cubes.  (Acid rain water, when frozen 
would look more like frozen tap ice cubes.  Can you explain? 
     Activity 5.0  Place tap water and distilled water in decomposition 
reaction jars. Insert electrode top and screw tight, plug into 
electrical outlet. Notice which jar of water is being decomposed and 
describe your observation.  NOTE: These are drinking waters.  Which 
would you prefer to drink.  (Observe student faces) 
     Activity  6.0  Discuss with class the purpose of the oil 
filtration system in an automobile.  Especially the purpose of the 
filter and oil relative to overall performance of car.  Compare and 
contrast the human excretory system relative to urine and water.  
Illustrate.  Also, explain the role of our skin and nose in the 
elimination of water.  Have students blow breath on cold mirror and 
note results.  Have students do research on the desert animals that 
never drink any water but make their water from their food.  Insert jar 
over burning candle and note the formation of water.  Explain.  
Students are now ready to focus on the true role of water in the human 
body.  Have them explain two or more ways by which water enters the 
human body and the purpose of bodily water.  Using anatomy/physiology 
charts, illustrate that over 70% of our daily food is water, over half 
of our body weight is water, that we lose about two liters of water 
daily through our sweat, urine, and breathed out moisture - as observed 
on the cold mirror.  Help students to understand that lots of water is 
good for the body in that it leads to a high volume of urine, causing 
the kidneys to do less work.  Concentrated urine is harder for the 
kidneys to remove.  Explain that this could be one of the reasons why 
some people have to go on the kidney machines or to take " dialysis 
treatments."  Another reason for lots of the "right kind of water" is 
that it may prevent urinary calculi (kidney stones).  Alert citizens 
are concerned about their environment and especially keeping our water 
clean.