Roche A. Samy
Acid Rain
Objective After this activity, the students will be able to explain and describe:
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1). What Acid Rain is and how it is formed;
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2). What the sources of this pollution are;
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3). What harm is done to animals, plants and the atmosphere including biosphere;
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4). What steps should be taken to remedy or control the situation.
Experiment In order to conduct this experiment, you would need a pH meter and two receptacles or glasses to collect the rain water.
The rain falling the first few minutes is most acidic. As the rain falls, it washes the atmospheric air, thereby dissolving most if not all the sulfur compounds, nitrogen compounds, fly ash and other particulates, to form the acid rain. Sulfur oxides mix with water to form sulfuric acid. Nitrogen oxides mix with water to form nitric acid. Carbon dioxides mix with water to form carbonic acid.
First collect the rain water that has been falling for the first five minutes. Next collect the rain water after thirty minutes, or less, if the rain stops earlier.
Measure the samples of water collected for acidity using a pH meter. The first sample may be between 5.00 to 5.5pH. The second sample of rain water may be 6.5 to 7.00pH, indicating that the first sample is more acidic than the second. You can repeat the experiments three or four times to ensure accuracy by repeating results.
Discussion Sulfur dioxide pollutant causes significant loss in crop yield each year. It originates from burning coal, or oil of high sulfur content. This pollutant is notorious for reducing atmospheric visibility, killing plants and rusting metals, and damage to buildings and paint. You might remember that one of the main cause of damage to the Statue of Liberty during the last 100 years was due to acid rain. Sulfur dioxide is also known to cause irritation of eyes, nose, throat and lungs. Of all the studies that have been conducted, more work has been done on the response of plant life to sulfur dioxide than any other air pollutant.
Nitrogen oxides are formed when burning fuels convert nitrogen and oxygen to nitrogen dioxide. This is an unpleasant smelling brown haze which along with being injurious to vegetation, irritates the eyes and noses of air breathing creatures. Trees and plants injured by air pollution develop symptoms peculiar to the specific symptoms. These symptoms provide a possible basis for diagnosing the types of pollutants that have been present.
Carbon Oxygen Cycle
By way of recycling in the biosphere, materials are used over and over again. In this case
two basic life
life processes are involved in the carbon-oxygen cycle
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These are respiration and photosynthesis.
Both animals and plants respire. Only green plants photosynthesize. During respiration carbon compounds are oxidized, and carbon dioxide (CO2) is released in the environment. During photosynthesis, green plants take water and CO2 from the environment and using sun’s energy, break down the water molecules. These hydrogen atoms from the water molecules combine with carbon dioxide which the green plants use to form carbohydrates (starch)-food of plants. When this happens, oxygen from water molecules is given off into the atmosphere. The atmosphere normally contains 21% oxygen and 0.04% carbon dioxide.
The second role of Carbon-Oxygen Cycle involves the making of organic compounds. Plants make food (carbohydrates) during photosynthesis. Other organic compounds are made from these carbohydrates. Plant-eating animals use these organic compounds to make their own protoplasm. These animals are in turn eaten by other animals. These animals also use the same compounds. All organic compounds contain carbon. When plants and animals die, the organic compounds in them break down. The carbon leaves their decaying bodies as carbon dioxide.
Rock fuels and mineral fuels play a small part in the carbon-oxygen cycle. Millennia ago, in the geologic past, the carbon of plants and animals were stored as coal and petroleum. When these fuels are burned, carbon dioxide is released into the atmosphere.
A diagram of the carbon-oxygen cycle is found in Appendix D.
Evaluation:
Vocabulary:
Define or use each of the following words in a sentence so as to bring out the meaning of each word.:
1). Acid Rain
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6). Photosynthesis.
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2). Sulfur Compounds
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7). Rock fuel
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3). Nitrogen Compounds
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8). Carbon-Oxygen Cycle.
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4). pH
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9). Millennia.
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5). Fly ash.
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10). Carbohydrate.
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Questions:
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1). Explain how Acid Rain is caused.
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2). List the various sources of pollutants that contribute to the formation of Acid Rain.
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3). What biological effects are caused by the different types of pollutants?
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4). Describe and explain with the aid of a diagram, carbon-oxygen cycle.
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5). How can you control the various types of pollution?
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6). How can you and your friends stop polluting the environment, your home, your class and your school?
(Think about soda bottles, beer cans, candy wraps, ice cream cups, straws, plastic spoons, papers, aluminum foils, plastics, matches, hamburger wraps, paper bags, sticks, paper cups, etc.)