standards. Polycarbonate has a few drawbacks. Its optical quality is not as good as CR-39 (standard plastic) and it costs more. While standard plastic costs $5‚ polycarbonate is $15. However‚ both materials will cost the same if you factor in ultraviolet protection. CR-39 allows some transmission of UVA and will require a UV blocking coating for full protection. This coating costs $10. Polycarbonate does not require a UV coating because it naturally blocks all
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of many free protons. H-II regions are areas where many large blue stars are formed. These blue stars would form inside a large cloud of hydrogen gas‚ giving off great amounts of ultraviolet light. This ultraviolet light then ionises the surrounding gas. The reason why they give off such enormous amounts of ultraviolet is because of their short life span. H-II regions can be several hundred
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1. Which of the following statements about heat is false? A) If heat flows into a system‚ the extra energy of the system appears in the form of internal energy. B) A hot object possesses more heat than a cold object. C) If the system and surroundings are in thermal equilibrium‚ there is no heat flow between them. D) A process in which heat flows out of a system is said to be exothermic. E) Heat is a form of energy flow. B is false. If you compare a cup of water at 25oC and a bath tub of
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It sits 340 miles above earth. It goes 5 miles a second. It weighs as much as two adult elephants. The technology on the Hubble Space Telescope is amazing. The cameras on The Hubble Telescope can see many types of light including infrared and ultraviolet light. HubbleSite.org states that the telescope uses a Cassegrain reflector telescope. A Cassegrain reflector has two mirrors. Light hits the main mirror and bounces to the second mirror. The second mirror is located in the hole in the center of
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typically placed at the top of mountains‚ so that they are above most of the water molecules in the air. Ultraviolet telescopes are placed in space‚ since the majority of ultraviolet radiation does not penetrate the Earth ’s atmosphere (Hubblesite‚ 2015). Most infrared light is absorbed by the Earth ’s atmosphere‚ although some can be observed from very high elevations. X-rays‚ gamma rays‚ and ultraviolet rays are generally only able to be observed in space (Hubblesite‚
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Harmful Threats to the Human Body There are a lot of bacteria that are good for human bodies‚ but there are also a lot of bacteria that’s very harmful to the human body. Bad bacteria can affect people from swimming in lakes and ponds. “Many of the world’s best-known disease outbreaks have been transmitted by water-borne bacterium.” Lakes and ponds are just un-treated drinking water. They have a lot of microorganisms in it that you cannot see. There are many ways to be contaminated by bacteria;
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Indoor tanning or frequent indoor tanning are widespread among high school students in the United States and it is a part of a bunch of potentially risky behaviours. [7]. Indoor tanning involves exposure to radiation that corresponds to an ultraviolet index of 13‚ which is significantly higher than the UV index of 8.5 which represents noon summer sun. Indoor tanning have significantly found to be associated with having part-time work‚ smoking‚ being physically active‚ and socially pressured that
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The ozone layer is a deep layer in the stratosphere‚ encircling the Earth‚ that has large amounts of ozone in it. The layer shields the entire Earth from much of the harmful ultraviolet radiation that comes from the sun. Interestingly‚ it is also this ultraviolet radiation that forms the ozone in the first place. Ozone is a special form of oxygen‚ made up of three oxygen atoms rather than the usual two oxygen atoms. It usually forms when some type of radiation or electrical discharge separates
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the volume of clean‚ dry air. Nitrogen: 78%‚ Oxygen: 21% 4. Ozone is a form of oxygen that combines three oxygen atoms into each molecule. Its presence of the ozone layer in our atmosphere is crucial because it absorbs the potentially harmful ultraviolet radiation from the Sun. 1.7 3. Ozone depletion seriously affects human health‚ animal life‚ and plant life. 4. The Montreal Protocol represents a positive international response to a global environment problem. 1.8 1. Pressure decreases
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from the earth’s surface there is a thin layer of gas forming just a small fraction of the earth’s atmosphere‚ without which harmful radiation from the sun would destroy all life on this planet? This is the ozone layer‚ which filters out harmful ultraviolet-B rays. Today‚ because of our negligence‚ the ozone layer is depleting. Ozone depletion occurs when the natural balance between the production and destruction of stratospheric ozone is tipped in favour of destruction. Although natural phenomena
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