Ultraviolet radiation - is electromagnetic radiation whose wavelength varies from border to border violet spectrum of X-rays.It is worth noting that the first mention of this phenomenon emerged in the thirteenth century.It was then that the Indian philosophers in his writings described the atmosphere in which contained violet rays, invisible to the naked eye.
At the end of the 17th century, when it was discovered by the infrared spectrum, scientists around the world took up the study of radiation at the opposite end of the light spectrum.That is exactly what was first discovered and studied by ultraviolet radiation.In 1801 IV Ritter discovered that silver oxide darkens quickly when exposed to visible light, related to the violet end of the spectrum.
Around the same time, scientists have come to the conclusion that light consists of three separate parts.This so-called visible light (or illuminating component), infrared and ultraviolet radiation (it is also reductive).Later research staff actively investigated the effect of ultraviolet radiation on living organisms, and its role in nature.
Ultraviolet radiation: properties and classification
Today ultraviolet rays are divided into three basic types, each of which has its own characteristics:
- UV-C, which is more known as gamma radiation.It should immediately be noted that they are very dangerous to the health of the human body.Fortunately, such radiation is almost completely absorbed by oxygen, ozone and water vapor ball even when passing through the planet's atmosphere.
- UV-B - is another type of radiation, which is also almost completely absorbed by the gaseous envelope of the Earth.Before the surface income is not more than ten percent.By the way, under the influence of these rays going melanin in human skin.
- UV-A.This type of rays almost reaches the planet's surface and virtually not dangerous for living organisms.Prolonged exposure causes premature aging of the skin.
As for the properties, for the beginning it should be noted that UV radiation is invisible to the naked eye.In addition, it has a high reactivity and a catalyst for a variety of natural reactions.High concentrations of UV light have antibacterial properties.And, of course, we must not forget that in small doses, it has a positive effect on the human body.
Ultraviolet radiation and its effects on the human body
Immediately it is worth noting that it is the ultraviolet rays promote the formation in human skin vitamin D, which, in turn, provides the normal calcium metabolism and good conditionthe skeletal system.Furthermore, the rays of the spectrum was responsible for the biological rhythm of living organism.It is proved that ultraviolet light increases the blood levels of the so-called "hormone of courage", which ensures the normal emotional state.
Unfortunately, ultraviolet radiation is necessary and useful only in small doses.Excessive exposure to these rays cause the opposite effect.For example, prolonged exposure to ultraviolet rays accelerates skin aging, and in some cases, and causes burns.Sometimes radiation leads to cell mutations, which can later develop into malignant tumors.
Increased UV radiation adversely affects the retina, causing a burn.Therefore, in the sunny season just need to use special protective glasses.
