Ultraviolet (UV) rays are invisible rays that come from the sun and can burn skin, hair and eyes if exposed too much. While harmful in excess, UV rays serve useful purposes like enabling vitamin D production and use in sterilization. Prolonged sun exposure increases skin cancer risk, so protection like sunscreen, clothing and sunglasses is recommended. UV rays constitute about 10% of sunlight and are both beneficial yet dangerous if not properly safeguarded against.

1. ULTRA VIOLET

2. What are UV rays?
 Ultraviolet (UV) rays are
invisible rays that are part of
the energy that comes from the
sun. UV rays can burn the
eyes, hair, and skin if these
parts of the body are not
properly protected, or if they
under go too much exposure to
the sun.
Nevertheless, UV rays are very
useful in our ecosystem.

3.  Ultraviolet (UV is a wavelength shorter than
that of visible light, but longer than X-
rays, that is, in the range 10 nm to 400 nm, c.
it is named like this because it lays above the
violet color in the seven colors of the
spectrum.

4.  UV light is found
in sunlight (where it
constitutes about 10%
of the energy in
vacuum) and is emitted
by electric arcs and
specialized lights such
as mercury lamps
and black lights. It can
cause chemical
reactions, and causes
many substances to
glow or fluoresce.

5.  UV rays assist our bodies in making vitamin D, which
strengthens bones and teeth and helps our bodies build
immunities to such diseases as Rickets and colon cancer.
UV rays are also used to treat psoriasis; the rays slow the
growth of skin cells, preventing the outbreak of the itchy
patches for which psoriasis is known. UV rays have various
commercial uses as well, including sterilization and
disinfection. Some animals can see UV rays, and UV vision
helps bees to collect pollen from flowers.

6.  In spite of all their positive uses, UV rays remain
very harmful for anyone who spends a large
amount of time in the sun without proper
protection.The most common effect of exposure
to UV rays is sunburn. Sunburn is the damage
caused to skin cells when they have absorbed
too much energy from UV rays. Sunburn causes
blood to rush to the affected area as the body
tries to cool the burn, and the damaged skin
ultimately peels away. In addition to the burning
pain on the skin, sunburn can ultimately
cause skin cancer.

7.  Skin cancer is often caused by prolonged
exposure to UV rays

8.  The best way to combat UV rays is with
bodily protection.Always wear protective
sunglasses and a hat to protect the eyes. A
hat will also protect hair from UV damage, as
well as the skin on the face and neck

9.  While the best protection for the
skin is long, loose clothing, this is
not always practical, so the next
best option is a
protective sunscreen.There are
many types of sunscreen, but they
all have a number indicating how
protective they are against harmful
UV rays.The higher the number, the
more protection they provide.
Always use sunscreen, even if you
will only be in the sun for a few
minutes. Be smart, cover up, use
sunscreen and enjoy the sunshine!

10.  http://www.youtube.com/watch?v=np-BBJyl-
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