Overview

The Origin
of Hair

Topic 1: Structures of
the Hair

Topic 1 Activity

Topic 1 Summary

Topic 2: The Layers of the Hair

Topic 2 Activities

Topic 2 Summary

Topic 3: Chemical Composition of Hair

Topic 3 Activities

Topic 3 Summary

Module Assessment

Developer Bio

New Evaluation Form

Activity 2.1 - Testing for Elasticity

This simple experiment will allow the student to test the elasticity of hair and observe the variations in elasticity between wet and dry hair.

Materials Needed

  • A strand of dry hair
  • A strand of wet hair
Directions
  1. Take the strand of dry hair and wrap it around your forefingers, making sure that your fingers are at least 2 inches apart.
  2. Gently pull the hair slowly. Notice how much it stretches.
  3. Take the strand of wet hair and again wrap it around your forefingers and gently pull it. Notice how much it stretches.

Follow-up

Which One Stretched More?

Healthy hair will stretch because the cortex of the hair is strong and elastic. If the cortex is damaged the hair strand will be weak and break more easily when it is pulled.

Normal dry hair is capable of being stretched about 1/5th of its length. Wet hair is able to be stretched 40 to 50% of its length.

Activity 2.2 - Testing for Cuticle Damage

In this exercise the student will be able to test the hair for cuticle damage, determining the degree of porosity in order to determine what products to use on the hair.

Hair that is damaged has a rough or course feel looks dull and is hard to manage. You can test for cuticle damage by making this simple test.

1. Take a strand of hair and run your thumb and forefinger along the strand against the direction of growth.

2. If the fingers slide smoothly, the hair has little or no cuticle damage.

3. If you feel "drag," you can assume that the cuticle is damaged or porous.

Porosity is the ability of hair to absorb moisture. The degrees of porosity are as follows:

a) Resistant porosity is hair that has closed cuticles and absorbs the least amount of moisture. This is poor porosity.

b) Average porosity is hair that is able to absorb moisture. This is considered good porosity and hair is in good condition.

c) Extreme porosity is hair that is damaged from chemicals and most of the cuticle is torn.

d) Uneven porosity is a combination of the two and is common in long hair.