LaMotte Water & Soil pH - Manual (Page 10)

NOTES TO THE TEACHER
The materials in this kit are provided as tools to conduct several
experiments. In addition to the procedures described in this manual, a
number of open-ended experiments are suggested to spur the student’s
imagination to investigate related problems. Students can use the
materials in this and other test kits to develop additional experiments.
AD DI TIONAL EX PER I MENTS FOR pH
1. Ask students to bring different water and soil samples from home.
Test for pH and compare the results. What is the general pH range for
soil and water samples? Are these ranges in general agreement with
the ranges stated in the text?
2. Add a pinch of lime (calcium carbonate, CaCO
3
) to the soil in a soil
sample bag. Mix thoroughly. Test the pH. What does lime do to the
soil? Why do farmers add lime to their fields?
3. Add a small amount of lime (calcium carbonate, CaCO
3
) to a water
sample. Test the pH. What does lime do to the water?
4. Obtain a water sample which is green with algae. Test the pH. Let
sample sit in the dark overnight. Measure the pH. Let the sample sit
in the sunlight for several hours. Measure the pH. How can algae
change the pH of water? What other organisms are present in the
water sample? How can they change the pH?
5. Fill a test tube almost full with sample water. Add several drops of
Tricel Indicator (5945) until a color of suitable intensity develops.
With a straw or tube blow air into the sample for a few minutes. How
does this change the pH of the sample?
HINT: For best results select water that is alkaline and use a control
tube to make the comparison.
6. Measure the pH of several household products, using the procedure
outlined on page 10.
7. Add a small amount of boric acid to a water sample. Add pH
indicator. Note color. Add a piece of an Alka-Seltzer tablet. What
happens as the tablet dissolves?
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