Why does the sun bleach our hair but darken our skin?
Answers:
good question!
Interesting. Let me know when you find out!
Hi. The ultraviolet breaks down the coloring agents in our hair while the skin tries to protect itself by increasing dark chemicals.
ironic, eh?
skin has a chemical called melatonin in it to help protect it from the suns rays.
I dont think hair has it so it lightens like a picture will if in direct sunlight.
Right, the darker your skin, the more melanin you have in your skin. melanin being the colour pigment you have in your skin ( inherited by your parents ).
People with darker hair, have darker skin, so they have more melanin.
When the sun's UV rays hit your hair, it breaks up the protein strands that your hair is made of ( don't forget your hair's dead when it leaves the root ). Yet your skin, contains this melanin ( the same thing that makes you tan) you skin cells are always dying and falling off, but when your skin has UV rays hit it, they send a hormone to send up the melanin, making your skin darker to slow the effects of further skin damage.
Hope this helps :D
your hair is dead material. It does not have life. Essentially letting your hair get sun bleached is like leaving a piece of paper/plastic toy in the sun. it will get scorched and lose its color.
Your skin is living. It gets burned. your top 1 or 2 of the 7 layers of your skin get burned and die.
Electromagnetic radiation from the sun ranges in energy from low (radio) to high (x-rays and gamma rays). At a certain energy level just above the light we can see (that is, ultraviolet), energy has the ability to damage biologic tissue or alter inorganic molecules. In one's hair (or in a t-shirt left out in the summer sun) there are pigment molecules which become degraded by constant bombardment from ultraviolet energy from the sun. This degraded pigmentation results in loss of pigment (color) in the hair. Less reflected color looks blonder (whiter).
Just because the ultraviolet energy from the sun is damaging to biologic tissues (namely, our DNA), our bodies have a system of dealing with it. Melanin is a pigment molecule nearly all humans have in their skin. It is what changes our skin color--that is, people with darker skin have more melanin within each pigment-containing cell than their lighter-skinned counterparts. Melanin absorbs ultraviolet radiation so that it cannot get to DNA and damage it. Because our biologic systems are exquisitly fine-tuned (and smart), the body knows when it is exposed to large quanitites of sun (over long periods of time--not acutely!!) and therefore when it will need more protection. A feedback mechanism senses exposure to UV radiation and leads to the consequent increase in the skin's pigment so as to better deal with the UV bombardment.
Nice question.
The skin becomes brown due to the release of a pigment into the skin to prevent damage from UV.
Hair already has this pigment, but hair is dead so there is no method to make the hair darker in responds.
Although I would like to suggest that if you covered your head during the summer your hair would darken due to the extra pigment not being bleached out.
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