8th grade science makes litmus paper

By 8th grade class

In March, the eighth grade class learned about pH indicators in Mrs. Schumacher’s science class. Mrs. Schumacher demonstrated how usual litmus paper worked; it would turn green if a sample was a base, blue if it was neutral and red or pink if it was an acid.

Cabbage juice contains a natural pH indicator that changes colors depending on the acidity of the solution. The pigment in red cabbage that caused the red color is called flavin, which is a water soluble pigment also found in apple skins, plums and grapes. For environmental and chemical engineers, the pH values of different liquids and solutions are important to consider, especially as they relate to bodies of water and explain the behavior of minerals and chemicals. For example, at acidic pH values, water begins to cause harm and destruction of ecosystems and minerals, as evidenced by acidic water dissolving the calcium carbonate that forms mollusk shells.

The students received instructions on how to make their own litmus paper out of red cabbage juice and coffee filters. To begin the experiment, the cabbage had to be first torn up, put in a flask and then mixed with water. Next, the class cooked the cabbage and water mixture over Bunsen burners. After letting it cool and absorb the juice for a couple of days, the cabbage juice was filtered out. Then the juice was dropped onto cut strips of coffee filters, they were also left to dry. Finally, the eighth grade class tested their red cabbage litmus paper to see if it worked, and it did!


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