Natural Indicators: Rose Petals
Emily B, Alexis B, Melissa D, Gabbi L, and Mary M
Introduction
Procedure
1.) Fill a small pot with water.
2.) Place on stove and wait until boiling.
3.) Peel the roses and place the petals into the water, stirring as you go. (We used four roses, but you can use however many you deem necessary.)
4.) Put lid on pot and let sit for ten minutes. Then continue checking the color of the water every five minutes until the desired dark red solution is reached.
5.) Place a bowl under a strainer and pour the pot's mixture (petals and liquid) onto the strainer and let liquid seep through.
Part II: Setting up pH Standards
1.) Label 7 test tubes with pH values of 1,3,5,7,9,11,13.
2.) Fill each test tube 1/4 full with standard pH solutions.
3.) Add 10 drops of the rose indicator to each tube and record the colors that correspond to each pH.
Part III: Testing the Samples
1.) Retrieve 5 test tubes and fill the separate tubes with each household substance.
2.) Add 10 drops of rose indicator to each test tube.
3.) Compare the colors of the household substances with the colors of the standard solutions from Part II. Estimate and record the pH of each solution.
Rose Indicator
pH Standards
Household Substances
Household Substances Without Indicator
Household Substances with Indicator
From left to right: Strawberry-scented hand sanitizer (8), contact solution (10), hydrogen peroxide (3), Fantastik (11), and distilled vinegar (5).
*Numbers in parentheses are estimated pH values.
Rose Petals
Data
Click on the link below to see our data table:
Conclusions
- After using red rose petals as a natural indicator, we learned that acids resulted in reddish pink colors, and bases resulted in more purple, green, and generally darker colors.
- Our indicator is better at detecting bases. We know this because when we got higher on the pH scale (towards bases), the color of the indicator varied much more than when it was creating the pH standards for acids.
- One problem we encountered during our experiment was that when we were testing our household substances, we felt like the contact solution and the strawberry-scented hand sanitizer didn't correlate to any colors that we created when making the pH standards. We "broke" our pH scale, so we had to estimate what two colors we felt the solutions were between.
- If we were to do this experiment again it might have helped us to test all the known pH values so we could better match the colors of our household objects to the pH standard we developed.