Friday, July 8, 2011

UV ray

UV Rays (Or Ultraviolet Rays) is a form of energy traveling through space. The most frequently recognized types of energy are heat and light. It is classified under “electromagnetic radiation”.

They travel in waves. Ultraviolet radiation is more energetic than visible radiation and therefore has a shorter wavelength. To be more specific: Ultraviolet rays have a wavelengthbetween approximately 100 nanometers and 400 nanometers whereas visible radiation includes wavelengths between 400 and 780 nanometers.

The major source of this rays is the Sun mainly. 99% of the Sun’s rays are in the form of visible light, ultraviolet rays, and infrared rays (also known as heat). Light enables us to see, and heat keeps us from being cold. However, ultraviolet rays often carry the unfortunate circumstance of containing too much energy. The energy contained in ultraviolet rays is higher, so instead of just causing the molecules to shake, it actually can knock electrons away from the atoms, or causes molecules to split. This results in a change in the chemical structure of the molecule. This change is especially detrimental to living organisms, as it can cause cell damage and deformities by actually mutating its genetic code.

Ultraviolet rays can be subdivided into three different wavelength bands, UV-A, UV-B and UV-C. They are classified on the amount of energy they contain and their effects on biological matter, ranging from UV-C to UV-A, from the most energetic and harmful to the least energetic and harmful.

Thankfully, the UV-C rays are blocked from the Earth’s Surface thanks to the presence of the Ozone Layer which breaks apart the bond of the molecule and absorb the energy. UV-B rays and UV-A have a lower energy level, thus longer wavelength, insufficient enough to split an ozone molecule, some extending down to the Earth’s Surface. Both UV-B and A are detrimental to health, particularly between the hours of 11am and 3pm.

Documentary on UV rays

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