AJ153

Can someone confirm if his answer is correct? UV has interesting proprieties compared to Alpha,Beta,Gamma Rays Question: I am currently taking first year physics in university and something that we were learning about peaked my interest. I know that alpha radiation is blocked by almost everything, beta by metallic and thicker material, and gamma by really thick materials, like a cm of lead. I was curious what completely blocks out uv radiation. I know that its non-ionizing so its not really like alpha, beta and gamma radiation. And clothing blocks some, but not 100% of it, unless you're wearing layers, or specially formatted fabrics. But does something like bristol board or a heavy paper block it 100%? I'm not sure if you know the answer, but I thought I'd give it a try. Thanks Answer: Ultraviolet is broken into three bands based on wavelength, UVA, UVB, and UVC: UVA 400 nm - 320 nm UVB 320 nm - 290 nm UVC 290 nm - 100 nm Materials can act very differently from one band to another. For instance, this page discusses sunscreen: http://www.fda.gov/fdac/features/2000/400_sun.html In general, the penetration depth of light into a material is a function of the wavelength of light. This rule begins to break down in the shorter-wavelength UV due to the high power of the photons. However, this is why very thin layers easily block UV light (for example, sunscreen or films on your sunglasses). Clothing is not a very good UV blocker because of gaps between fibers. Synthetic materials are also frequently transparent to UV, but I think most organic dyes are good UV absorbers, but they also break down under prolonged exposure (due to ionizing). While not a definitive result, I can safely say that plain white paper is not a good blocker from experience in the lab. Anything thick, with dye (like bristol board) will block transmission of nearly 100% of UV light. The board will break down under prolonged exposure. Best, Curtis Source: .allexperts.com/q/Physics

Mr.Cuthber you have relied my OCD-ness to UV! Many thanks to the explanations! I gained alot of knowledge, and really do appreciate it! Love the humor to the other John

Thank you for your replys, many thanks John! I think this information will aid me for better heath and prevent my familys skin problems with UV! Also additional protection of invested material (furniture,antics,paintings) from UV damage, In a study UV damage is too house hold things are the following So scientifically UV Radiation (lets say A) will not pass solid opaque material or any sort of matter depending on thickness? I remember water either reflects the UV or it goes only so far (e.g. the ocean). With glass I remember in 8th grade chem class our teacher told us glass filters a good amount of UV. Also I live pretty far from the equator (Chicago Land area) and being the winter time with no snow (UV reflection) the sun shines down onto my room only around 7:30-10 A.M when the sun is at its weakest. So I'm not worrying to much, but I do have a mild OCD. Which is why I love science since it answers all my OCDness. The thickness I'm talking about for cardboard is like this and the paper Im talking about is like this Reasons why I would like too know is because aside from studying science I also seek art to calm my OCD, the only thing is I want to store my paintings from the harmful UV radiation, and boxs and packaging paper envelopes is all I have really. I really want to know if this is enough UV protection giving the variables of morning UV rays near Chicago, IL in the middle of the winter. Again many thanks for taking the time to answer my questions! I really do appreciate this!

What can UV radiation from the sun pass through? Can it pass through any of these materials Opaque/semi Opaque - House glass (ones in everyday normal windows) - Cardboard (used for packaging) - Paper - Plastic - Water - Cloth (Like window blinds) - Metal - Umbrella As I grow older I'm more curious in UV protection for home,car, and outdoors since my family has a history of skin problems caused by sun UV Radiation, I remember learning this in Chemistry class, but I totally forgot about what UV can penetrate through. Thank you for reading.

interesting, Gosh I wish I still had my chemistry/physics note book, I remember taking notes on UV radiation. Would me just rapping the UV sensitive objects with cloth or adding another box inside the box protect it? My mom would not approve using her cooking stuff, for my artwork.

Can Sun UV-A and UV-B penetrate through cardboard? If I were to say store something that UV sensitive (fades very fast to UV rays). Would it be safe?

I keep hearing that windows filter Sun UV rays? some say its 99% others say its 50%, I know windows filter UV-B, but not all of UV-A. Lets say are controlled factor is a sunny morning (fall-winter season in Canada) morning when UV's are the weakest, and fall-winter when there even weaker. Would UV penetrate through a window? If so lets say I filter it by covering the window with construction paper (material used for shipping envelopes)? How strong would the UV Rays be if even existent? Would any of the following below be effected? reason why I want too know -Having a bed for a babe next to a window in the early morning? -People with sensitive skin - fear of Indoor items/clothing that sit next to windows form fading.

Very interesting! Thank you for the information! On another note Can this topic be moved to Other Science section, I feel as this would be more fitting for this type of question.

In my room I have a clothing cubby near a window (window that has one sheet of glass, with half an inch of space between another layer of glass. So two layers basically with half an inch of space inbetween) , and only in the morning from 7:30-8:50 AM does the sun leak through the window onto my cubby. I have window blinds (the ones with the slats) and it does block most of the sun, but it still leaks some sun light onto the cubby. I've had it like this for 2 months (from October till now), my concern is will the morning uv ray be enough to bleach/lighten my clothing? I really like my cubby in its location and the sun only shines on it for an three hours a day. (easy to get cloths, and perfect aesthetically in my room) yet some of the cloths just chill there since I dont ware stuff for months due to weather. In addition will that shipping construction paper (that type of material used to make shipping envelopes) block the UV rays as well? Ghetto as it sounds I have a medium sized shipping paper, that material used to make those brown shipping envelopes with the plastic bubble wrap coating on the outside of it. Taped on the upper part of the window blocking 40% of the upper part. (no one notices it back yard a forest) and I never have my blinds or window open. Will this help block the in addition to the window that blocks UVA that fades clothing? I was told in a science article the following "Most people know that UV exposure is highest around noon and in early afternoon, in the summer and at low latitudes. Correspondingly, EPA recommends to reduce time in the sun between roughly 11:00 AM to 4:00 PM during summer in zones that observe daylight saving time. However, things are not as simple as they might seem. Indeed, UV intensity varies dramatically during the day as well as between seasons and across latitudes. (See the charts of radiation intensity vs time of day/year for UVA and UVB. For example, a sunny winter morning in Canada presents virtually no risk of sunburn, whereas a sunny summer noon in Egypt virtually guarantees it (assuming no sun protection). Yet, sunlight can contribute to skin aging even outside peak hours, summer season, or low latitudes. This is partly due to the fact that skin aging is caused predominantly by UVA. While both UVA and UVB rise towards midday, summer and lower latitudes, the changes are much less dramatic for UVA than fo"