What Makes Hair Curly? | LifesLittleMysteries.com
Curly hair tends to be much drier than straight hair because it is easier for the oils secreted from the scalp to travel down the shaft of a straight hair than a curly one (this is why curly hair often turns into frizzy hair).
And as anyone with curly hair knows, humidity can make your hair even curlier (or frizzier). The reason: Hair fiber absorbs the water and forces the shaft to revert to its original (less straight) structure.
Why Humidity Makes Your Hair Curl | Surprising Science
Hair’s chemical structure, it turns out, makes it unusually susceptible to changes in the amount of hydrogen present in the air, which is directly linked to humidity. Most of a hair’s bulk is made up of bundles of long keratin proteins, represented as the middle layer of black dots tightly packed together in the cross-section at right.
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This type of bond is permanent—it’s responsible for the hair’s strength—and isn’t affected by the level of humidity in the air.
But the other type of connection that can form between adjacent keratin proteins, a hydrogen bond, is much weaker and temporary, with hydrogen bonds breaking and new ones forming each time your hair gets wet and dries again. (This is the reason why, if your hair dries in one shape, it tends to remain in roughly that same shape over time.)
Hair Science News: Temporary Changes
Hydrogen bonds are weak physical cross bonds in the hair. When hair is wet, the hydrogen bonds are broken, allowing hair to be formed into a new shape.
When the hair is dried and cooled, they rejoin, allowing the hair to take on the new shape.
Video: How to Keep Your Hair Straight | eHow.co.uk
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