Water Purification

Wilson, Wardell Raster School

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
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