| Debriefing |
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pH Test Kit Design
You should have a test kit containing 1-2 clean vials or test tubes.
You should have used an indicator solution for measuring a pH between
5.0 and 6.4. The indicators list in the Common
pH Indicators chart suggests that methyl red or bromothymol
blue would be the best indicator. You should have created a pH color
chart using solutions with known pHs for a range between 5.0 and 6.4.
Answer to the Investigative Question
The data you collected should have indicated the change of pH per X
grams of lime. Since hydrangeas bloom pink around a pH of 6.0 - 6.4,
the pH should have been raised 0.8 -1.2 units from an initial soil condition
pH of 5.2. Approximately, a total of 0.1181 grams of lime would be needed
to raise the pH to 6.2, allowing for the hydrangea bush to bloom a bright
pink color in a 4.5" pot (or .02625 g/ sq. in).
Congratulations! You now have the skills to grow
a healthy hydrangea bush, as well as one of your own to take home with
you. Play with the pH of your soil to watch the color of the flowers
change between vibrant shades of pink and blue. But remember that exteme
conditions outside its healthy growing conditions can be very harmful
to your plant.
