Gutter, Nadine Robeson High School

Objectives 1. The student will understand the definition of a pesticide. 2. They will recognize why pesticides are used. 3. The student will understand why certain pesticides are no longer used. 4. The student will be able to make a judgement about the use of pesticides. 5. The student will understand the nature of an enzyme. Materials a variety of fresh fruits and vegetables petri dishes water vegetable oil florence flask a variety of pesticide containers naphthalene data sheets damaged fruits/vegetables/leaves labels graduated cylinders two small stuffed animals exactly alike sewing needle thread black tape two small plants exactly alike wood splints, cotton balls, paper, cotton cloth Recommended Strategy Preplanning 1. Display the fresh fruits and vegetables and the pesticide containers on the demonstration table. 2. Pour about 20 mL of the vegetable oil into a florence flask and label it "human body fat". 3. Pour about 20 mL of the water into a florence flask and label the flask H20.
4. Place a small amount of the naphthalene crystals into a petri dish
and label the dish "DDT"".
5. Prepare the two small stuffed animals by labeling them as baby #1
and baby #2. Tape or sew back the ears, arm, eyes, nose, etc. of #2.
6. Prepare the two plants by labeling them as plant #1 and
plant #2. Remove the leaves from plant #2.

Introduction Begin the demonstration by having the students observe the damaged vegetables/fruits/leaves. Get some oral responses to the question, "what happened to this produce?" Have students circle demo table to observe the fruit/vegetable display. Ask students if they can get the same or better quality items near where they live. Relate quality and quantity of produce to pesticide use by farmers. At this time you should point out the different types of pesticides that were brought in the containers on the demo table. Briefly discuss pesticide use in relation to limited resources and growing world populations. Tell students that chemists are constantly working to produce pesticides that do not have negative effects on the environment. Procedure 1. Discuss the pesticide classes chlorinated hydrocarbons, defoliants and organophosphates in this order. The student should record the class, name, helpful and harmful effects of a particular pesticide on his data sheet. 2. Demonstrate the actions and effect of the pesticides by simulation. Below are some simulations which show actions and effect of some pesticides. Students should do each simulation before the action or effect of the pesticide is covered in the discussion. action/effect simulation a)how DDT builds up in the bodies drop a few of the naphthalene of aquatic animals and plants crystals into a florence flask mammals eat filled with 20 mL of water b)how DDT builds up in toxic drop a few of the naphthalene amounts in the fatty tissues of crystals into a florence flask mammals filled with 20 mL of vegetable oil c)to show the effect of defoliants use plant #1 and plant #2 on forest use cotton and cotton cloth d)to show defoliant effect after a use wood splints and paper second application (losses to industry) e)to show birth defects caused by use baby #1 and baby #2 defoliants f)to show how organophosphates have students contract and inhibit the enzyme relax their arm muscles:then acetylcholinesterase have them continuously contract the arm muscle 5 or 6 more times 3. At the end of the demo ask students the following questions: On the basis of the data collected,decide if: a) pesticides should be continued to be used b) pesticide use should be banned c) chemist should continue working to develope pesticides that do not produce negative effects on the environment. Give reasons for your answer. References Medeiros, Robert W. Chemistry, A Modern Perspective. D. Van Nostrand Company:
New York, London, Cincinnati, Toronto, Melbourne, 1973. pp. 300-314.
Jarvis, Bruce and Paul Mazzocchi. Form and Function. Harper and Row:
New York, Hagerstown, San Francisco, London, 1978. pp. 12-60.
Stryer, Lubert. Biochemistry. W. H. Freeman and Company: San Francisco,
California, 1981. pp880-893.
Cram, Donald and Jane. The Essence of Organic Chemistry. Addison-Wesley
Publishing Company: Menlo Park, California, 1978. p. 139.

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