Introduction Water hardness is an ongoing problem across the globe. While not detrimental to our health, there are many issues that arise from having hard water in households. You may be asking, what is hard water? Isn’t it all liquid? The “hardness” of water actually refers to the presence of divalent cations, or ions with a +2 charge. In drinking water, these are most commonly Ca2+ and Mg2+ ions (“Water Hardness”). Water hardness can cause a buildup of minerals on surfaces such as dishes, sinks, showers and pipes. While the aesthetic problems are not that important, the buildup in the pipes can be very harmful. The scale that builds up causes utility bills to increase because more energy is required to deliver water to its final…show more content… The water will turn to blue when you reach this point. Once you find how many drops of EDTA it took, you can calculate the concentration of calcium and magnesium in the water, as seen in the results section. EDTA is not always precise since the turning point will often lie between drops, which can result in a large margin of error, especially for small samples. For a more accurate test, we turn to AA, or Atomic Absorption Spectrophotometry. This water hardness test uses a machine to aspirate the water sample. This gas then is burned in a flame, and a light of a range of wavelengths is passed through it. The machine then calculates the amount of divalent cations in the water by comparing the relative levels of light passed through the sample at each wavelength to known atomic absorption levels. You then use a trend line from known samples’ readings, to figure out what the concentration of calcium or magnesium there is. These two different tests are both used in this lab so that we can be assured we’ve done them right. The hardness of one test should be similar to the hardness obtained from the other. Using these tests, we created a hypothesis to test.
Our group was testing which part of Pennsylvania has the highest mineral content and hardness of their water. Our samples came from a Pittsburgh well (694 Forbes Rd. New Castle PA 16101), State College tap (478 E Calder Way State College PA 16801) and Philadelphia tap (6705 Springbank Lane Philadelphia