Cherry as a Natural Indicator
By Ryan G, Sami W, David N, and Devin T
Introduction
The purpose of this lab was to determine which household substances were acids or bases using a natural indicator. Indicators change color in the presence of an acid or base, and the color indicates the pH value. An acid has pH lower than 7 and dissociates to create a hydrogen ion, and a base has pH higher than 7 and dissociates to create a hydroxide ion. The household substances we will test are Febreeze, Tide, vinegar, Green Works, and Shout. We predict that the vinegar will be an acid, and the other four will be bases.
Procedure
The following pictures show the procedure we used in this experiment.
1. Crush the Cherries
We put the cherries in a bowl and used a potato masher to crush and then strained them into a liquid.
2. Set Up Test Tubes With pH Levels
We put solutions with pH's 1, 3, 5, 7, 9, 11, and 13 in a test tube rack.
3. Add Indicator to Each pH Value
We added our indicator to each pH test tube to see the color change to compare our household substances to later.
4. Set up Household Substances
We set up our five household substances, which we would add our indicator to.
Data
The following pictures show the data we determined after conducting our experiment.
pH 1
Color of solution with pH 1
pH 3
Color of solution with pH 3
pH 5
Color of solution with pH 5
pH 7
Color of solution with pH 7
pH 9
Color of solution with pH 9
pH 11
Color of solution with pH 11
pH 13
Color of solution with pH 13
Initial Color of Febreeze
The color of the Febreeze before adding our indicator
Final Color of Febreeze
The color of Febreeze after adding our indicator, which we determined was a pH value of about 14
Initial Color of Shout
The color of the Shout before adding our indicator
Final Color of Shout
The color of the Shout after adding our indicator, which we determined was a pH value of about 10
Initial Color of Green Works
The color of the Green Works before adding our indicator
Final Color of Green Works
The color of the Green Works after adding our indicator, which we determined was a pH value of about 14
Initial Color of Vinegar
The color of the vinegar before adding our indicator
Final Color of Vinegar
The color of the vinegar after adding our indicator, which we determined was a pH value of about 14.
Initial Color of Tide
The color of the Tide before adding our indicator
Final Color of Tide
The color of the Tide after adding our indicator, which we determined was a pH value of about 10
Conclusions
When conducting this experiment, we learned that using cherries as an indicator was not very efficient. The pH value solutions did not differ in color a very noticeable amount, which made it difficult to determine the exact pH value. They were all red, while the acids (pH 1, 3, and 5) were lighter red, and the bases (pH 9, 11, and 13) were slightly darker red. Due to the small range of colors, and our indicator being darker more often than not, we determined that it is better at detecting bases than acids. We struggled to determine the pH values of any acids, because our indicator was very dark to begin with, which caused the substances to always appear to be closer to the base's colors, even if they were supposed to be acids. Also, our indicator solidified a bit in the time between mashing up the cherries, and actually using it, so that made it difficult to use. If we were to do this experiment again, we would have to mash the cherries much closer to the time when we are actually using the indicator.