SLC _17B - Water Pollution

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					                         SLC #17B - Water Pollution
                                5th Grade
                        Mary Gilstrap, Mrs. Smith & Ms. Brown

References:

   •   www.iit.edu/~smile/bi8701.html - This was the source for the lesson plan, which
       was modified from the outline presented in this website.
   •   The attached worksheet was modified from one created by Meghan Knapp.

Benchmarks:

         SLC 17: Analyze the impact of human activity on the ecosystems of the earth
         CPS Benchmark: SLC 17B: Students will identify the impact of human activities
on the earth’s ecosystem (pollution, conservation of natural resources, erosion, and soil
fertility).

Objectives:

      To give the students an idea of the impact of the various pollutants with which
humans contaminate our water, as well as some techniques used to filter water.

Materials:

             •   Large “filtering tube” (or glass funnel)
             •   Large glass tank or jar
             •   Bag of charcoal pebbles, sand, and gravel - from a fish store
             •   Micropore filter paper (coffee filters work)
             •   Petri dishes
             •   Chlorine (Either liquid or powder, from a pool supply store)
             •   A strainer (like from your kitchen), or screening
             •   Household product pollutants - These can be any number of things…
                 some good examples are: motor oil, food dyes, scraps of paper, soil,
                 leaves, clay balls, coffee grounds.
             •   Tablespoon measure
             •   Large Bucket (~5 gallons)

Initial Demonstration:

       Show students the large bucket filled with water. Than demonstrate the
tablespoon with water in it. The bucket represents most of the water on earth- salt water
that we cannot drink. The tablespoon represents the small amount of fresh water on Earth
that we can use.
Target Observations:

   •   Students should realize that fresh, drinkable water is a small percentage of the
       water on earth.

Target Model:

   •   Although there is a lot of water on earth, much of it is not usable, and fresh water
       is really a delicate resource.


Procedure:

       What is pollution? What pollutes our water? Pollutants are represented by
household products and added to the large glass tank filled with water. (Examples of
pollutants can be found in the materials section.) Ask, “This water started out as clean
fresh water… would you drink it now?”

       Students should immediately see the impact of the pollutants on the water. The
water will be dirty. They should realize this water is not usable anymore (at least not for
drinking)

Target Revised Model:

       •   Fresh water is a limited resource
       •   Pollution makes water “dirty”.

Procedure:

        Now the students should come up with some ways to clean the water. Their
brainstorming should be listed on the board. The following methods will actually be
used:
    1. Screening
    2. Sedimentation
    3. Filtration
    4. Chemical Treatment

Students may have to be led to examples of some of these answers. Their brainstorming
should be grouped then, under the four categories above, which can then be introduced as
vocabulary.

    Then, form the students into four-five teams. (Four works well, as there are four
different cleaning methods). Have each team decide which cleaning methods they will
use, and in what order.
   With help, have the students perform the following activities if they chose these
methods:

   1. Screening: Filter some of the polluted water through a household strainer. Ask
      students for observations as to what pollutants this cleans (large particles).
   2. Sedimentation: Take the screened water and let it settle. More impurities should
      settle out. Again, students should observe that this removes smaller but clearly
      visible dirt particles.
   3. Filtration: The following items should be added into the filtering tube or funnel.
      First, a piece of filter paper. Then, one layer of charcoal, then one layer of sand,
      and then one layer of pebbles. Observations should be made by the students.
      Explain to them what each of the “filters” is. See if they can figure out why they
      are placed in the order described above. (Answer: The water should hit the
      “bigger” filter first, and get out larger particles, and then be refined at each step,
      until finally hitting the filter paper). Smaller dirt particles which were not
      removed by earlier processes should now be removed - the water should look
      clearer.
   4. Chemical Treatment: Since this process does not make a visible change, the
      following activity can be done. Give each group a Petri dish with three small
      slices of boiled potato in each dish. Onto one slice a drop of the polluted water
      from the tank should be placed; onto a second slice a drop of the filtered water
      from the filtering funnel should be placed; onto the third potato slice a drop of the
      filtered water and a drop of chlorine mixed with this filtered water should be
      placed. Cover the dish and allow for bacterial growth for a few days. Students
      can now compare the chemically treated water to the filtered, and to the most
      impure water.

        Ask students what they saw when the water was cleaned by each process.
Remind them that doing this in reality is expensive and time-consuming. Although we
can clean up polluted water, we don’t want to have to. Lead this into a discussion of
what human processes pollution comes from and what we could do to keep water from
getting polluted.

Target Revised Model:

   •   Pollutants make water dirty, but it is possible to clean it.
   •   Pollutants are often caused by things humans do, and we should try to minimize
       these things.
   •   This is especially important since there is not very much fresh water on earth.

Summary:

       There is a very limited amount of drinkable fresh water in the world. This water
can be made unusable if it becomes contaminated or polluted, usually by humans. The
water can be cleaned, but that this is very expensive and time consuming. Polluting the
water should be avoided as much as possible.
         Clean It Up - Water
              Pollution
Group Members:
Materials Manager: ______________________
Recorder: _______________________________
Presenter: _______________________________
Teacher Liason: __________________________

Your group may choose up to four of the methods to
clean your water. The materials manager will gather
the necessary supplies and return them. The recorder
for your group must record the method(s) used, the
cost, and the time it took to clean your water. At the
end of the class, the jars of water will be ranked from
cleanest to dirtiest. Record your ranking. Your
presenter will tell the class which methods you used,
and describe whether the method was effective and
cost efficient. If you have questions, only the teacher
liaison may ask the teacher for help.


The order we chose to clean our water was:
  1. __________________________________
  2. __________________________________
  3. __________________________________
 4. __________________________________
Method     Cost    Time     Effective? How?

				
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