We
feel happy when the sun is out - why?
This is because sunlight helps increase the production of serotonin (the
feel good brain chemical) good for controlling sleep patterns, body temperature
and mood swings.
What
are UV rays?
Sunlight emits invisible ultraviolet rays of which there are 3 types;
UVC, UVB and UVA.
The ozone and oxygen in the atmosphere absorb all the UVC and most UVB
rays before reaching the earth's surface.
UVA and UVB rays present the most harm to humans. However, depletions
in the ozone layer may cause increased exposure to all harmful UV rays.
Can
the skin defend itself?
Yes but not completely. Melanin, a skin pigment present in varying amounts, acts as the first defence against the sun by absorbing and reacting with harmful UV rays. With prolonged exposure to the sun more Melanin is produced thus affecting the colour of our skin. The tan is your body's attempt at protecting itself from the sun.
"A sunburn develops when the amount of UVB and UVA exposure is greater than what can be protected against by the skin's melanin" www.kidshealthorg | 
