How does skin tan?
Skin develops extra melanin when it is exposed to strong sunlight. Tiny grains of melanin are produced in the skin cells and spread to produce an even suntan, which helps to protect against Sun damage. This even happens in people with naturally dark skin. You can get sunburn if you are exposed to the Sun’s rays for too long, because the damage will be done before the protective melanin can develop. You should always use protective sun cream and limit the amount of time you spend in the sunshine.
How do cuts and grazes heal?
When you cut or graze yourself, the blood clots to prevent bleeding. Clotting is caused by substances in the blood. Together with small particles called platelets, these substances produce masses of fine fibres when they are exposed to air. They block the wound and prevent more blood loss. New cells grow rapidly into the wound, replacing the damaged tissue. Soon the clotted material, called a scab, falls off and clean, new skin is revealed underneath.
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