Wavelength - 1 x 10 ^ - 8 to 5 x 10 ^ - 8 m
Discovered by Johann W. Ritter
In 1801 Ritter conducted experiments with silver chloride and a prism.
He projected a beam of sunlight through the prism, which split the beam into
the colors of the spectrum. He them put chloride in each color to see the
outcome. The red caused a small change while the deep violet darkened the
chloride. Ritter placed chloride in the lightless area just beyond the violet
and it darkened as it were in a smoky fire. The was evidence of another wave
form just barely higher than the violet of visible light. It is now known as
ultraviolet or UV light.
Man-Made UV rays:
UV rays can be made
artificially by passing an electric current through a gas or vapor, such as
The Effects of Ultraviolet on the Skin -
UV waves injure cells in the epidermis (outer layer) by diffusing into
the inner layer and causing an enlargement of vessels. Blisters can occur due
to too much exposure. If there is overexposure, blisters can leave scars or can
cause skin cancer
UV rays are used in:
Ultraviolet waves are effective in killing bacteria and viruses.
Hospitals use germicidal lamps that produce these waves to sterilize equipment,
water and air in operating rooms. It is also used to treat acne and psoriasis.
The Food and Drug industry uses germicidal lamps to disinfect various
types of products and their containers. The main use of ultraviolet is in the
manufacturing integrated circuits.
Scientists learn about the
make up and energy levels of atoms by studying UV rays. Experts also learn abut
distant stars and galaxies by analyzing the UV rays that are given off.
Artificial sources of ultraviolet light are often used to stimulate the effects
of solar ultraviolet radiation in the study of the deterioration of materials
on exposure to sunlight
Ultraviolet waves are used to identify materials by the glow or
fluorescence under them. They are used to make black lights. May food and drug
companies use germicidal lamps to disinfect various types of products, and
UV from Space:
The sun and lightening are
celestial bodies that emit ultraviolet waves. Electrical sparks in the air
causes an emission of UV. Ultraviolet light is emitted by the sun. Ultraviolet
radiation is related with hot objects. Examples are stars with surface
temperature in range of 50,000 to 1000,000 K and hot gas clouds found between
Dangers associated with Ultraviolet Waves:
Overexposure to these ultraviolet waves can cause painful eye
irritation, sunburns and skin cancer. These waves can also cause the
destruction of plants and the breakdown of the ozone layer. Ultraviolet
exposure can also damage and kill plants. Some photobiological effects include
cell mutation, interference in the division of cells and an increased rate of
High quality sunglasses
protect the eyes from UV rays, and sunscreen to protect the skin from sunburn.
Other devices include UV detectors, phototubes, photovoltaic cells, and
Detecting Ultraviolet Rays:
We use rockets and a series of orbiting satellites to detect UV rays
that come from space.
Experiments indicate that bees, birds, butterflies and other insects can
see ultraviolet light. The reflection of UV rays off wings help insects
Birds have the ability to see ultraviolet light as well as the primary
colors. Research indicates that this ability plays a role in bird's
reproductive habits, as they prefer mates that detect ultraviolet light.
Ultraviolet rays cause
chemical reactions in plants. If they are overexposed to it, it could kill
People who contributed:
Mary Grace Flanigan