Monday, September 29, 2008

Atom


The atom is the smallest unit of an element that retains the chemical properties of that element. An atom has an electron cloud consisting of negatively charged electrons surrounding a dense nucleus. The nucleus contains positively charged protons and electrically neutral neutrons. When the number of protons in the nucleus equals the number of electrons, the atom is electrically neutral; otherwise it is an ion and has a net positive or negative charge. An atom is classified according to its number of protons and neutrons: the number of protons determines the chemical element and the number of neutrons determines the isotope of that element.
The name atom comes from the Greek ἄτομος/átomos, α-τεμνω, which means uncuttable, something that cannot be divided further. The concept of an atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers. In the 17th and 18th centuries, chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods. During the late 19th and early 20th centuries, physicists discovered subatomic components and structure inside the atom, thereby demonstrating that the 'atom' was not indivisible. The principles of quantum mechanics were used to successfully model the atom.
Relative to everyday experience, atoms are minuscule objects with proportionately tiny masses that can only be observed individually using special instruments such as the scanning tunneling microscope. Over 99.9% of an atom's mass is concentrated in the nucleus, with protons and neutrons having roughly equal mass. Each element has at least one isotope with unstable nuclei that can undergo radioactive decay. This can result in a transmutation that changes the number of protons or neutrons in a nucleus.Electrons occupy a set of stable energy levels, or orbitals, and can transition between these states by absorbing or emitting photons that match the energy differences between the levels. The electrons determine the chemical properties of an element, and strongly influence an atom's magnetic properties

biodiversity

Biodiversity is the variation of life forms within a given ecosystem, biome or for the entire Earth. Biodiversity is often used as a measure of the health of biological systems. The biodiversity found on Earth today consists of many millions of distinct biological species, which is the product of nearly 3.5 billion years of evolution.

Evolution and meaning
Biodiversity is a portmanteau word, from biology and diversity. The Science Division of The Nature Conservancy used the term "natural diversity" in a 1975 study, "The Preservation of Natural Diversity." The term biological diversity was used even before that by conservation scientists like Robert E. Jenkins and Thomas Lovejoy. The word biodiversity itself may have been coined by W.G. Rosen in 1985 while planning the National Forum on Biological Diversity organized by the National Research Council (NRC) which was to be held in 1986, and first appeared in a publication in 1988 when entomologist E. O. Wilson used it as the title of the proceedings of that forum.The word biodiversity was deemed more effective in terms of communication than biological diversity.

Since 1986 the terms and the concept have achieved widespread use among biologists, environmentalists, political leaders, and concerned citizens worldwide. It is generally used to equate to a concern for the natural environment and nature conservation. This use has coincided with the expansion of concern over extinction observed in the last decades of the 20th century.

The term "natural heritage" pre-dates "biodiversity", though it is a less scientific term and more easily comprehended in some ways by the wider audience interested in conservation. "Natural Heritage" was used when Jimmy Carter set up the Georgia Heritage Trust while he was governor of Georgia; Carter's trust dealt with both natural and cultural heritage. It would appear that Carter picked the term up from Lyndon Johnson, who used it in a 1966 Message to Congress. "Natural Heritage" was picked up by the Science Division of The Nature Conservancy when, under Jenkins, it launched in 1974 the network of State Natural Heritage Programs. When this network was extended outside the USA, the term "Conservation Data Center" was suggested by Guillermo Mann and came to be preferred.

Saturday, September 20, 2008

Where is Indian hockey going?



The Indian Hockey team at the 1936 Berlin OlympicsField hockey is India's national game. Until the mid 20th century, India dominated international hockey, winning 8 Olympic gold medals, the World Cup in 1975 and were runners-up in the 1973 World Cup. The Indian player Dhyan Chand, arguably the most famous Indian hockey player, was described as a 'wizard' by the European press. However, India's recent performance have been below par and India is currently ranked 8th in the world.

Even though cricket has by far overtaken hockey in popularity, hockey still strikes an emotional chord especially with the older generation. India's men's hockey team recently won the Asia Cup held in Chennai, defeating South Korea by a very convincing margin. However, they failed to qualify for the Beijing Olympics, the first time they have not made it to the Olympics since 1928.
Who is to be blamed,well that would be our KPS Gill.The new generation should take up hockey and help regain the place of Indian hockey in international forum.

tennis-the favourite

Roger Federer


Roger Federer born August 8, 1981) is a Swiss professional tennis player who is currently ranked World No. 2. He was the World No. 1-ranked player for a record 237 consecutive weeks, from February 2, 2004, through August 17, 2008. Many tennis critics, legendary players, and current players consider him the greatest tennis player everFederer has won thirteen Grand Slam singles titles (three Australian Open, five Wimbledon, five US Open), four Tennis Masters Cup titles, and fourteen ATP Masters Series titles. Federer holds many records in the game, including having appeared in ten consecutive Grand Slam men's singles finals (2005 Wimbledon Championships through the 2007 US Open) and eighteen consecutive Grand Slam singles semifinals (2004 Wimbledon - present). He also holds the open era records for consecutive wins on both grass courts (65) and hard courts (56). At the 2008 Summer Olympics, Federer won the men's doubles gold medal for Switzerland, partnering with Stanislas Wawrinka. He has a storied rivalry with Rafael Nadal, who succeeded him as the World No. 1 player.
In 2008, he was named Laureus World Sportsman of the Year for a record fourth consecutive time.