Acid Rain vs Normal Rain
The hydrological cycle is important in order to keep the balance of how water is cycled. The water, which is in oceans, lakes, and other reservoirs on the earth surface, is getting evaporated in the daytime. Trees and other organisms also give out a considerable amount of water. The evaporated water is in the atmosphere, and they aggregate and form clouds. Due to the air currents, the clouds can travel to farther locations than where they are made. The water vapor in the clouds can come back to the earth surface in the form of rain.
Rain is the main form in which the evaporated water from the earth surface is coming back to the earth. This is also known as liquid precipitation. Atmosphere contains water vapor and when they are saturated in a certain place, they form a cloud. The saturation of air is easier when it is cooled than when it is hot. For example, water vapor can be cooled when it contacted with a colder surface. In order for the rain to take place, the water vapor, which is in the form of tiny droplets, should combine together and form a larger water drop. This process is known as coalescence. Coalescence takes place as the water droplets collide with each other, and when the drop is heavy enough it falls down. The rainfall patterns vary according to the geographical differences. Deserts get minimum rainfall over the year, whereas rainforests get a very high rain fall. In addition, it is affected by various other factors like wind, solar radiation, human activities, etc. Rain is very important for the agriculture. Earlier, people totally depended on the rain water for their agriculture. Today also most of the agriculture depends on the rain water.
Water is a universal solvent. When raining, the rain water tends to dissolve substances, which are dispersed in the atmosphere. Today the earth’s atmosphere has been highly polluted due to human activities. When there are sulfur dioxide and nitrogen oxide gases in the atmosphere, they are easily dissolved in rain water and come down as sulfuric acid and nitric acid. Then the pH of the rain water becomes less than 7, and we say that it is an acidic. Over the past few decades, the acidity of rain has increased significantly due to the human activities. SO2 is produced during fossil-fuel burning, and in industrial processes, H2S and S are produced. Nitrogen oxide is also produced from fossil fuel burning and power plants. Other than the human activities, there are natural processes where these gases are produced. For example, SO2 is produced from volcanoes, and NO2 is produced by soil bacteria, natural fires, etc. Acid rain is harmful to the soil organisms, plants, and aquatic organisms. Moreover, it stimulates corrosion of metal infrastructure and other stone statues.
What is the difference between Normal Rain and Acid Rain?
• Acid rain contains a large amount of sulfur dioxide and nitrogen oxide gases dissolved in it than the normal rain.
• Usually, the atmosphere contains acidic gases from natural processes. Therefore, anyway, they are dissolved in rain water and the pH of it is slightly acidic. But the acid rain pH is far more less than this value, which can come down to pH 2-3 sometimes.
• Acid rain is harmful to the organisms, and to the infrastructure whereas normal rain is not.