Science 30 January 1999 Grade 12 Diploma Examination
Science 30 January 1999 Grade 12 Diploma Examination Science 30 January 1999 Grade 12 Diploma Examination
Scoring Guide – Long Answer 2 January 1999 Diploma ExaminationSCORE4Standard ofExcellence32AcceptableStandard10SCORING DESCRIPTIONSThe response is complete, well organized, and reflects thorough understanding andlogical consistency of thought. The description of the environmental problemsassociated with energy production are complete and correct. Opinions about the stepsthat should be taken in the future are imaginative and realistic. Appropriateexamples and logical arguments are used to support opinions.The response is mostly complete, organized, and reflects correct understanding.The description of the environmental problems associated with energy production arecorrect. Opinions about the steps that should be taken in the future are complete andrealistic. Examples and logical arguments are used to support opinions.The response is organized, and is generally logical and consistent . The descriptionof the environmental problems associated with energy production are generallycorrect. Opinions about the steps that should be taken in the future are logical. Someexamples and arguments are used to support opinions.The response is incomplete, disorganized, and reflects poor understanding. Thedescription of the environmental problems associated with energy production are poor.Opinions about the steps that should be taken in the future are not logical. Examplesand arguments are not used to support opinions.The response does not address the question at a Science 30 level.
Sample Answer – Long Answer 2The main methods of electrical energy production are coal-fired, nuclear, and hydrogenerating power stations. The main environmental problems associated with the use offossil fuels such as coal are global warming and acid deposition. The carbon dioxideproduced by combustion causes a greenhouse effect in the atmosphere. Some scientiststhink that this will lead to disastrous changes in global climate and may cause widespreaddeath to many species including humans. Acid deposition is caused when sulphur oxidesand nitrogen oxides react with moisture in the air. This is causing the destruction ofmany terrestrial and aquatic habitats around the world. Leaching of heavy metals intowater habitats and thermal pollution are also problems associated with fossil fuelpoweredstations.Nuclear power production produces long-lasting radioactive wastes. Safe disposal ofthese wastes over thousands of years is not possible presently. Background radiation maycontinue to rise to catastrophic levels if accidents at power plants occur or if radioactivewastes leak into the environment. Not only will the organisms on which we rely forsurvival be affected, but many human deaths due to cancer will occur.While hydro power produces few contaminants it produces significant environmentaleffects. Damming a river causes flooding of the upstream part of the river. This changesthe habitats and displaces many kinds of plants and animals. It may also cause moreheavy metals to leach into the water. Silting may cause changes in the drainage patternsthroughout the area around the dam.Alternate forms of electrical energy such as photovoltaic cells, wind generators, tidalpower, and geothermal power stations have fewer environmental effects. Thedisadvantages of these power sources is the cost of building and maintaining theequipment necessary to run them, and in some cases, they are available in a limitednumber of places.The main strategy for the immediate future should be to reduce the consumption ofenergy. This can be done by educating people about the effects of energy production onthe environment. It might be necessary to lower our expectations for some of the luxuriesthat we now enjoy. People should be taught methods of conserving energy. Increasingthe cost of using energy might also be implemented by taxing excessive energy use.Besides reducing energy use, it is also necessary to develop cleaner ways of producingenergy. Development of technologies such as solar energy, wind, tidal, and geothermalpower stations should have a high priority. Nuclear fission may also provide a relativelyclean form of energy in the future.
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Scoring Guide – Long Answer 2 <strong>January</strong> <strong>1999</strong> <strong>Diploma</strong> <strong>Examination</strong>SCORE4Standard ofExcellence32AcceptableStandard10SCORING DESCRIPTIONSThe response is complete, well organized, and reflects thorough understanding andlogical consistency of thought. The description of the environmental problemsassociated with energy production are complete and correct. Opinions about the stepsthat should be taken in the future are imaginative and realistic. Appropriateexamples and logical arguments are used to support opinions.The response is mostly complete, organized, and reflects correct understanding.The description of the environmental problems associated with energy production arecorrect. Opinions about the steps that should be taken in the future are complete andrealistic. Examples and logical arguments are used to support opinions.The response is organized, and is generally logical and consistent . The descriptionof the environmental problems associated with energy production are generallycorrect. Opinions about the steps that should be taken in the future are logical. Someexamples and arguments are used to support opinions.The response is incomplete, disorganized, and reflects poor understanding. Thedescription of the environmental problems associated with energy production are poor.Opinions about the steps that should be taken in the future are not logical. Examplesand arguments are not used to support opinions.The response does not address the question at a <strong>Science</strong> <strong>30</strong> level.
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