Hair porosity is the hair's ability to absorb and retain moisture. The porosity of your hair affects how well oils and moisture pass in and out of the outermost layer of your hair. Normal porosity is the ideal situation.
Hair Porosity Test
How to measure?
Take your hair strand and put it into a mug filled with water.
High-heat styling tools (curling/straightening irons, hot rollers, blow dryers on high heat without diffusers).
Over Expose to Sun
A lot of sun exposure or a lot of swimming in chlorinated water or salt water.
Excess use of cosmetic
Bleaching or highlighting immediately make hair more porous.
What is Hair Elasticity?
It is an essential indicator of a healthy head of hair. It is the capability of the hair strand to stretch and return to its previous form without breaking.
Hair Streching Test
How to measure?
On Dry Hair
On Wet Hair
A dry hair can stretch 20-30% of its own length before it breaks. If your hair is 2 inches (5 cm) long, if it has very good elasticity, it should stretch to 2.4-2.6 inches (~6 to 7 cm) when dry and up to 3 inches (~8 cm) when wet.
Measure the length of your dry hair pulled straight, but not stretched.
Hold your hair so it lines up with the end of the ruler, press that end down on a hard surface, Grasp the other end (be sure to note how much length is lost due to your grip) and pull steadily and gently until the hair breaks. Write down the measurement as "dry".
Repeat with a few more dry hairs.
A wet hair can stretch up to 50% of its own length before it breaks. If your hair is 2 inches (5 cm) long, if it has very good elasticity, it should stretch to 2.4-2.6 inches (~6 to 7 cm) when dry and up to 3 inches (~8 cm) when wet.
Now for the wet-hair test. First soak your hair in water (preferably distilled or non-chlorinated water) for 2 minutes. Then stretch and measure as before. Record these as "wet" measurements.
How to improve elasticity?
If you have low Elastcity
The hair does not stretch. It contains too
much protein and breaks quickly. Use
shampoo that are mild.