Students Learn about the Acidity of Water

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Students in Mr. Knight's fifth grade science classes are discovering how organisms affect the acidity of  water.  Students are learning how to use BTB as an indicator of carbon dioxide. First, students added BTB to water and noticed that the water turned blue, meaning no acidity.  Then, they blew bubbles into the water and saw that the water turned from blue to green to yellow, meaning that the water was not very acidic. "We discovered that carbon dioxide makes the water more acidic," said Mr. Knight.  "We tested water that housed our goldfish and our water that just had elodea, an aquatic plant. We found out that the goldfish water turned yellow because the goldfish gives off carbon dioxide into the water, while the elodea turned blue because plants take in carbon dioxide turn the day."  Students also found out that during darkness, elodea was turning the water yellow, which meant that plant releases carbon dioxide at night when there is no sunlight.  "At the end," said Mr. Knight, "We were  able to use our Chromebooks to compare other testing that was found on the FOSS website and compare our findings."