Project Question: I was trying to show that bottled water is as pure as tap water. I let samples of water evaporate on glass disks and looked at the residue. Now thru research I have found that the residue is magnesium and calcium, whcih is good for you. Should I now say that pure water will have more residue because of good minerals? I thought the glass would be clean with no residue on the purest water.
Project Due Date: November 10,2008
Project Status: I am finished with my experiment and analyzing the data
I was trying to show that bottled water is as pure as tap water. I let samples of water evaporate on glass disks and looked at the residue. Now thru research I have found that the residue is magnesium and calcium, whcih is good for you. Should I now say that pure water will have more residue because of good minerals? I thought the glass would be clean with no residue on the purest water. Please help
Hi Starmaster,
Welcome to the Ask an Expert forum. What brand or type of water is your bottled water? Is it "spring water"? "Distilled water"? is it filtered by any method? In scientific terms, if a water is more "pure" it would tend to have less reside after evaporation. However, bottled water companies can use this term however they want. For example, a spring water might have a lot of dissolved calcium and magnesium and other minerals, but the bottling company might call it "pure" to make it more appealing to customers. I once ran water quality analyses for "pure spring" bottled water, and the water was more contaminated than most local wells in the area.
Water with high concentrations of calcium and magnesium is sometimes called "hard water." There do not seem to be any major health effects (good or bad) from drinking hard water. There is a brief discussion of the topic here: http://en.wikipedia.org/wiki/Hard_water ... iderations
Looking forward to hearing more about your experiment.
Project Question: I was trying to show that bottled water is as pure as tap water. I let samples of water evaporate on glass disks and looked at the residue. Now thru research I have found that the residue is magnesium and calcium, whcih is good for you. Should I now say that pure water will have more residue because of good minerals? I thought the glass would be clean with no residue on the purest water.
Project Due Date: November 10,2008
Project Status: I am finished with my experiment and analyzing the data
Thanks for the help. I had many types of bottled water, most said spring and one called FIJI says it is artesian water. I was just having trouble understanding my results because my hypothesis was the water with the least residue was the purest. My family collects rain barrel water and I even let that evaporate. It showed the least amount of residue, but I would not want to drink it. I did ph stirps on all my water too and they were pretty much all the same.
"Spring" water and "Artesian" water are waters that have percolated below the ground and have been in contact with sediments and/or rocks for many years, centuries, or longer. Some of the minerals in the ground slowly dissolve into the water, which is why you see the residue after the water has evaporated.
Rain water originates from water vapor in the atmosphere which tends to have low concentrations of dissolved minerals.
In theory, spring and artesian waters should tend to have a higher pH than the rain water. However, there are exceptions to this rule.
I hope that helps.
Chris
Now thru research I have found that the residue is magnesium and calcium, whcih is good for you. Should I now say that pure water will have more residue because of good minerals? I thought the glass would be clean with no residue on the purest water. Please help 