uv rays- what can they do and what are they?
970333
UV rays are just a "color" of light that cannot be seen by humans. It has too short of a wavelength. UV is typically broken down into UVA and UVB. \nAmongst other things, UV light can be used for gettnig a nice tan, curing some adhesives, damaging most kinds of plastics (take a look at the dashboard of an old car - that cracking is due to UV damage)
280135
Both reasons are correct.  The UV rays have less "stuff" to travel through in the air and atmosphere, so they have a stronger effect.\n\nAlso the snow does have a reflective and intensifying quality that it passes to the UV rays.
494172
NO, ANY TAN IS ACTUALLY A SYMPTOM OF CELLS THAT HAVE BEEN DAMAGED. TANNING BEDS HURT EVEN WITHOUT BURNING. UVA RAYS MAY BE LINKED TO MELANOMA, PREMATURE AGING, AND IMMUNE SYSTEM DAMAGE. A TAN DOESN'T MAKE VITAMIN D. THOUGH YOU DO NEED SOME SUNSHINE FOR VITAMINS, IT TAKES VERY LITTLE FOR YOUR BODY TO PRODUCE VITAMIN D, FAR LESS THAN IT TAKES TO GET A TAN.
994458
Sunblock works in one of two ways - as a chemical absorber to prevent harmful UV sunrays from penetrating the skin by converting it to heat, or as a physical blocker to reflect the rays.
842036
Filter the major part of incoming UV radiation.
1176203
One way it actually interacts is by catalysing chemical reactions-various spectrums of light increase atomic bonding between different chemicals and atoms. Of course there is heat, the solar radiation excites atoms and increases their activity, generating heat. Most everything else is optics, like things we say as white reflect almost all the light hitting them and things we see as black absorb the entire spectrum of visible light.
598470
Yes uv rays are still emitited through clouds. but not at night.
437654
UV Light is really good for skin conditions like psoriasis, you can ask you doctor to reefer you for it, or you can buy a small portable face tanner - my dad used one for his psoriasis and it worked really well, but talk to you doc first to see how long/often you should use it
651796
UV radiation, the portion of sunlight that causes sunburns, increases 10% for every 1000 foot rise in elevation. Ask any skier if it is possible to sunburn in the winter at elevation.  \nSo, at very extreme altitudes, say above 15,000 feet you have 2 1/2 times the intensity of UV. The power of UV has nothing to do with ambient heat. Sunburned skin and eye damage is quick to occur at these altitudes.
883308
Dear Andrea,\nSunlight contains UV radiation which again are of 3 types UV-A, UV-B and UV-C. UV-C is absorbed by the Ozone layer above our atmosphere. UV-A and UV-B reach the earth's surface.\nUV-A and UV-B are both harmful for our eye. They both act on different parts of our eyes causing damage.\n\nIn general, UV rays can cause early cataracts, retinal degenerations, Sun burns (maculopathies) in retina, Viterous degenerations, corneal xerosis, conjunctival xerosis etc and much more..\n\nSo please wear a sunglass if you go out in sun...\n\n:-)\n\nZubin J
254009
Light is a form of atomic radiation.  When an electron drops to a lower shell it releases a photon.  \n\nOther radiation can stimuate the energy in atoms and cause electrons to bounce up and down levels creating photons as well.
101502
Irradiation (e.g. strong x-ray or gamma) may be harmful to microorganisms working at the destruction of the object, but it won't halt chemical processes outside biodegration, and may even harm molecules. Ultraviolet light will harm pigments and surfaces. Modest amounts of infrared irradiation may help to dry an object to prevent molding, but other methods like freeze-drying are preferable.\n\nFor a very narrow cause of damage, irradiation may help. In general, it won't.
653585
tanning is a reaction of your skin to protect itself from UV rays, melanin is produced to help absorb some of the radiation.  Sunburn is an actual burn, damage done from overexposure to the radiation.  What determines the difference is the intensity of the radiation and the duration.
176519
High frequency radiation like ultraviolet radiation contains more energy, and it can damage the DNA in your cells, causing cancer. \n\nIt can also cause bad burns.
1114517
Although the concentration of ozone in the ozone layer is very small, it is vitally important to life because it absorbs biologically harmful ultraviolet (UV) radiation emitted from the Sun. UV radiation is divided into three categories, based on its wavelength; these are referred to as UV-A, UV-B, and UV-C. UV-C, which would be very harmful to humans, is entirely screened out by ozone at around 35 km altitude.\n\nUV-B radiation is the main cause of sunburn; excessive exposure can also cause genetic damage, resulting in problems such as skin cancer. The ozone layer is very effective at screening out UV-B; for radiation with a wavelength of 290 nm, the intensity at Earth's surface is 350 million times weaker than at the top of the atmosphere. Nevertheless, some UV-B reaches the surface. Most UV-A reaches the surface; this radiation is significantly less harmful, although it can potentially cause genetic damage.\n\nDepletion of the ozone layer would allow more of the UV radiation, and particularly the more harmful wavelengths, to reach the surface, causing increased genetic damage to living things.\n\nDNA sensitivity to UV\nTo appreciate how important this ultraviolet radiation screening is, we can consider a characteristic of radiation damage called an action spectrum. An action spectrum gives us a measure of the relative effectiveness of radiation in generating a certain biological response over a range of wavelengths. This response might be erythema (sunburn), changes in plant growth, or changes in molecular DNA. There is much greater probability of DNA damage by UV radiation at various wavelengths. Fortunately, where DNA is easily damaged, such as by wavelengths shorter than 290 nm, ozone strongly absorbs UV. At the longer wavelengths where ozone absorbs weakly, DNA damage is less likely. If there was a 10% decrease in ozone, the amount of DNA damaging UV increases, in this case, by about 22%. Considering that DNA damage can lead to maladies like skin cancer, it is clear that this absorption of the Sun's ultraviolet radiation by ozone is critical for our well being.\n\nAmount of ozone\nThe "thickness" of the ozone layer—that is, the total amount of ozone in a column overhead—varies by a large factor worldwide, being in general smaller near the equator and larger as one moves towards the poles. It also varies with season, being in general thicker during the spring and thinner during the autumn. The reasons for this latitude and seasonal dependence are complicated, involving atmospheric circulation patterns as well as solar intensity.
717662
Ozone (O3) gets broken down when hit with UV rays, absorbing all the energy of the rays.  O3 absorbing UV rays means our DNA in our cells isn't.\n\nO3 + uv -> 02 + O-\n\nThe O- ion is very reactive and will bind almost immediately to another neighbouring O- ion to make O2, or to a neighbouring O2 molecule to make O3.\n\nCheck this website out for a full layout of good environmental science.\nhttp://www.chm.bris.ac.uk/motm/ozone/high.htm
1113985
Even the hightest SPF screen won't completely prevent UV rays from touching your skin. That's what tans you. The sunscreen is to help you stay in the sun longer without burning. It always needs to be reapplied every few hours. You'll tan if you're outdoors and exposed, believe me.