Ultraviolet Waves
What are they?
Ultraviolet (UV) light has shorter wavelengths than visible light. Although UV waves are invisible to the human eye, some insects, such as bumblebees, can see them. This is similar to how a dog can hear the sound of a whistle just outside the hearing range of humans. The sun is a source of the full spectrum of ultraviolet radiation, which is commonly subdivided into UV-A, UV-B, and UV-C. These are the classifications most often used in Earth sciences. UV-C rays are the most harmful and are almost completely absorbed by our atmosphere. UV-B rays are the harmful rays that cause sunburn. Exposure to UV-B rays increases the risk of DNA and other cellular damage in living organisms. Fortunately, about 95 percent UV-B rays are absorbed by ozone in the Earth's atmosphere.
How They're Made
Ultra-Violet light is made by special lamps, for example, on sun beds. It is given off by the sun in large quantities.
Uses
Uses for UV light include getting a sun tan, detecting forged bank notes in shops, and hardening some types of dental filling. You also see UV lamps in clubs, where they make your clothes glow. This happens because substances in washing powder "fluoresce" when UV light strikes them - they absorb the UV and then re-radiate the energy at a longer wavelength. The lamps are sometimes called "blacklights" because we can't see the UV coming from them. When you mark your posessions with a security marker pen, the ink is invisible unless you shine a UV lamp at it. Ultraviolet rays can be used to kill microbes. Hospitals use UV lamps to sterilise surgical equipment and the air in operating theatres. Food and drug companies also use UV lamps to sterilise their products. Suitable doses of Ultraviolet rays cause the body to produce vitamin D, and this is used by doctors to treat vitamin D deficiency and some skin disorders.
Dangers
Large doses of UV cause sunburn and even skin cancer. Fortunately, the ozone layer in the Earth's atmosphere screens us from most of the UV given off by the Sun. UV exposure can also harm the retina in your eyes, which is why it is a good idea to wear sunglasses when the sun is strong.
Future Possibilities
If there is less pollution worldwide, and the greenhouse effect decrease, there is a possibility that the Earth will be more protected from harmful UV rays and waves.
Ultraviolet (UV) light has shorter wavelengths than visible light. Although UV waves are invisible to the human eye, some insects, such as bumblebees, can see them. This is similar to how a dog can hear the sound of a whistle just outside the hearing range of humans. The sun is a source of the full spectrum of ultraviolet radiation, which is commonly subdivided into UV-A, UV-B, and UV-C. These are the classifications most often used in Earth sciences. UV-C rays are the most harmful and are almost completely absorbed by our atmosphere. UV-B rays are the harmful rays that cause sunburn. Exposure to UV-B rays increases the risk of DNA and other cellular damage in living organisms. Fortunately, about 95 percent UV-B rays are absorbed by ozone in the Earth's atmosphere.
How They're Made
Ultra-Violet light is made by special lamps, for example, on sun beds. It is given off by the sun in large quantities.
Uses
Uses for UV light include getting a sun tan, detecting forged bank notes in shops, and hardening some types of dental filling. You also see UV lamps in clubs, where they make your clothes glow. This happens because substances in washing powder "fluoresce" when UV light strikes them - they absorb the UV and then re-radiate the energy at a longer wavelength. The lamps are sometimes called "blacklights" because we can't see the UV coming from them. When you mark your posessions with a security marker pen, the ink is invisible unless you shine a UV lamp at it. Ultraviolet rays can be used to kill microbes. Hospitals use UV lamps to sterilise surgical equipment and the air in operating theatres. Food and drug companies also use UV lamps to sterilise their products. Suitable doses of Ultraviolet rays cause the body to produce vitamin D, and this is used by doctors to treat vitamin D deficiency and some skin disorders.
Dangers
Large doses of UV cause sunburn and even skin cancer. Fortunately, the ozone layer in the Earth's atmosphere screens us from most of the UV given off by the Sun. UV exposure can also harm the retina in your eyes, which is why it is a good idea to wear sunglasses when the sun is strong.
Future Possibilities
If there is less pollution worldwide, and the greenhouse effect decrease, there is a possibility that the Earth will be more protected from harmful UV rays and waves.