Hardness is the quality in water that is imparted by the presence of dissolved salts, especially calcium and magnesium. Hardness refers to how many mineral particles there are in water. The harder the water is, higher the contents of minerals. A geologist is a person who specialized in geologic research and study; a hydrologist is a geologist that studies the circulation, distribution, and properties of the waters of the earth and its atmosphere. A particle is a tiny or small bit. A mineral is any of a class of substances occurring in nature. Calcium is a silver-white divalent metal, and magnesium is a light ductile, silver-white, metallic element that burn with a dazzling white light. Dissolving is when you make a solution by mixing a solvent with a solute. Pure water is neither acidic nor basic, but rainwater is slightly acidic; as it passes through mineral deposits, it reacts with the minerals for them to dissolve in water.
When you wash dishes, if you have hard water you would need more soap to get the dishes cleaned. When measuring the hardness of water you can compare the measure of suds that form with liquid soap. Calcium and magnesium dissolved in water determines the hardness. Water hardness (mg/L)＝Ca(mg/L)×2.497 ＋ Mg(mg/L)×4.118. Water hardness is measured in grains per gallon, in milligrams of calcium (Ca) per liter, or parts per million. Hardness is not the same everywhere; it varies throughout the United States. Water is harder in Florida, New Mexico, Arizona, Utah, Wyoming, Nebraska, South Dakota, Iowa, Wisconsin and Indiana. In other places in the United States water is softer. There is slightly hard, moderately hard, hard and very hard water. Soft water has to have less than a grain of calcium or magnesium.
Hard water isn’t as useful as soft water. The importance of softening water for a domestic purpose is beneficial because of the less amount of soap is required. Hardness in water may occur in two forms, as temporary hardness or as permanent hardness. Water that is hard temporarily can be softened when boiled. Water that is permanently hard cannot be softened when it is boiled. Hard water can make it difficult to lather up when washing your hands or clothes, and hard water can damage equipment and shorten the life of fabric and clothes. Hard water is not a hazard. The minerals in hard water are good for your body. Calcium and fluoride helps prevent teeth decay. It is also very good for your skin. Hard water is also cheaper than soft water.
You can get hard water from anywhere while soft water is mainly filtered and paid for by most people. Water can vary in hardness. It could be soft, slightly hard, moderately hard, hard, and very hard. The hardness of water is expressed by grains per gallons, milligrams per liter (mg/l) or parts per gallon (ppm). Soft water usually contains 0 – 17.1 mg/l or ppm with 0 – 1 grains per gallon, slightly hard water is classified with 17.1 – 60 mg/l or ppm and 1 – 3.5 grains per gallon, and moderately hard is expressed as 60 – 120 mg/l or ppm and 3.5 – 7.0 grains per gallon. Hard water is shown as 120 – 180 mg/l or ppm with 7.0 – 10.5 grains per gallon and very Hard has 180 & over mg/l or ppm with 10.5 & over grains per gallon.
* http://ga.water.usgs.gov/edu/characteristics.html#Hardness * http://www.sciencebuddies.org/science-fair-projects/project_ideas/Chem_p094.shtml#background * http://www.water-research.net/hardness.htm
* “Mechanics of the Household” by E. S. Keene