Effect of pH on Hair Resilience

Short Description
understanding the chemistry of hair care, including the role of pH, … If you damage your hair (e.g., by using the wrong types of hair care products) …

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Content
Effect of pH on Hair Resilience
Student Sheet
Name ___________________________
There are three components to this lesson, outlined below. Complete the
activities in order to answer the central question of this lesson: “How does
understanding the chemistry of hair care, including the role of pH, help in the
development of better hair care products?”
Part I: Determining the pH of shampoo samples
Using the shampoo samples given to you by your teacher, determine the pH of
each of the samples. You can determine pH by using a method familiar to you,
such as using pH strips or probes. Record the pH of your shampoo samples
below:
Shampoo name pHPart II: Treating hair samples in solutions of varying pH
Complete the following activity in your lab group and answer the questions that
follow.
Procedure:
1. Obtain 4 wooden splints; 4 test dishes; 20 strands of the same type of hair;
and 4 strips of tape.
2. Clean the 4 dishes in pH neutral solution and rinse thoroughly with distilled
water. (Be sure to clean all glassware after each use so that the samples are
not contaminated.)
3. Label the test dishes pH 2.0, pH 6.0, pH 10.0, and pH 12.0. Add 10 mL of the
appropriate pH solution to each of the dishes.
4. Tape 5 strands of hair to each splint with one end fastened, and the other end
free to be immersed in the test solutions. Label the ends of each splint with
pH 2.0, pH 6.0, pH 10.0, and pH 12.0.
5. Put each splint into the corresponding solution. Allow the hair to be exposed
for 10 minutes.
6. Remove the hair sample and rinse with distilled water. Allow the strands to air
dry.
7. Grasp the ends of the pH 2.0 sample and pull gently. Record observations of
the following in the data table:…