December 19, 2006 1:38am CST
what is ozone layer?
7 Jan 07
Direct evidence that carbon dioxide assimilation is the "dark reaction" of photosynthesis came from the work of Melvin Calvin and his associates at the University of California at Berkeley. Calvin started with the hypothesis that carbon dioxide is changed to carbohydrate in a series of separate chemical reactions. He reasoned that if he could stop the process part way, he would find intermediate compounds. If the plant took up radioactive carbon dioxide, the intermediate compounds would be "tagged." They would contain radioactive carbon and could be distinguished from all the other carbon compounds in the cell. If these "tagged" intermediates were separated and identified by paper chromatography and related techniques, the "path of carbon" from carbon dioxide to carbohydrate would become known.
19 Dec 06
ozone is a gas that occurs naturally in our atmosphere. most of it is concentrated in the ozone layer, a region located in the stratosphere several miles above the surface of the Earth. Although ozone represents only a small fraction of the gas present in the atmosphere, it plays a vital role by shielding humans and other life from harmful ultraviolet light from the Sun. Human activities in the last several decades have produced chemicals, such as chlorofluorocarbons (CFCs), which have been released into the atmosphere and have contributed to the depletion of this important protective layer. When scientists realized the destructive effect these chemicals could have on the ozone layer, international agreements were put in place to limit such emissions. As a result, it is expected that the ozone layer will recover in the coming decades.
22 Jan 07
ozone layer is the blanket to the earth that protects the sun's harmful UVrays falling on us..its getting effetced due to CFC's mainly relased by refrigirators,aeroplanes..and this reduces the density of ozone in the stratosphere whcih will make the UV rays easily penetrate throughthe atmosphere..this we call forming holes...so now a days scientists have discovered these holes on the poles...the servere threat is that the holes have been forming over the antarctica and because which the ice there is starting melting down...this is only the beginnig..and if the holes further spread the rate at which ice there melts will exponentially increase and the average sea level rises up and the greatest threat is to the coastal areas where someday there wil be no cities there.....we have to open our eyes atleast now and find out the possible solutiosn to reduce this effect..everone now try to share how to control this ...
26 Dec 06
Ozone is simply a molecule consisting of 3 oxygen atoms, which reacts strongly with other molecules. Ozone is created in the stratosphere when high energy uv radiation causes on O2 molecule to split. The free oxygen atoms collide and react with other O2 molecules to form O3. Production is highest where the solar uv is the greatest eg near the tropics, but once created, the ozone is then circulated towards the poles by the atmosphere. The amount of ozone in the stratosphere can vary with location, season and even day to day climatic conditions. The process of ozone creation is what makes the O3 in the atmosphere very effective at shielding the Earth from harmful uv radiation, which can cause many biological problems, such as skin cancer. However, due to its high reactivity, the uv found in the tropospher at ground level can aslo be dangerous as a toxic pollutant which is harmful to plants and lung tissue, and is a major cause of smo
22 Dec 06
The ozone layer, or ozonosphere layer (rarely used term), is the part of the Earth's atmosphere which contains relatively high concentrations of ozone (O3). "Relatively high" means a few parts per million - much higher than the concentrations in the lower atmosphere but still small compared to the main components of the atmosphere. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958 Dobson established a worldwide network of ozone monitoring stations which continues to operate today. The "Dobson unit", a convenient measure of the total amount of ozone in a column overhead, is named in his honor.
19 Dec 06
Regular oxygen that we breathe is O2. Ozone is O3. There is a layer of ozone in the atmosphere that protects the Earth from ultraviolet radiation. It is created from ultraviolet radiation. The UV rays strike a normal oxygen molecule, splitting it into 2 seperate Oxygen atoms. These atoms react with other O2 molecules to create ozone. The ozone molecule is again broken up by UV radiation, and produces an O2 molecule and a O atom. The process repeats back and forth. In the news, the "ozone hole" is considered a huge environmental problem. Chlorofluorocarbons (CFC's) found in old refridgerators, air conditioners, and aerosol cans supposedly caused irrepairable damage to the ozone layer. But as CFC's are heavier than air, there is no way for them to get up into the stratosphere to damage the ozone layer. Also, they are too reactive to reach the upper atmosphere. They would much more likely react with a substance closer to the source (therefore, close to the surface of the Earth.) There are "holes" in the ozone layer around the poles, but this is due to a lack of exposure to UV radiation in these areas. Less UV rays = less ozone.