Thursday, December 27, 2007

Tsunami

A tsunami is a series of waves shaped when a body of water, such as an ocean, is rapidly displaced. Earthquakes, group movements above or below water, volcanic eruptions and other underwater explosions, landslides, large meteorite impacts and testing with nuclear weapons at sea all have the potential to produce a tsunami. The effects of a tsunami can range from imperceptible to devastating. The word tsunami comes from the Japanese words meaning harbor and wave. For the plural, one can either follow usual English practice and add an s, or use an invariable plural as in Japanese. The term was created by fishermen who returned to port to find the area neighboring their harbor devastated, although they had not been conscious of any wave in the open water. Tsunamis are general throughout Japanese history; approximately 195 events in Japan have been recorded.

A tsunami has a much smaller amplitude (wave height) offshore, and a very long wavelength, which is why they generally pass unobserved at sea, forming only a passing bulge in the ocean. Tsunami have been historically referred to as tidal waves because as they approach land, they take on the characteristics of a vicious onrushing tide rather than the sort of cresting waves that are formed by wind action upon the ocean. Since they are not really related to tides the term is considered misleading and its treatment is discouraged by oceanographers.

Tuesday, December 18, 2007

Pets

A pet is an animal kept for companionship and enjoyment, as opposed to livestock, laboratory animals, working animals or sport animals, which are kept for economic reasons. The most popular pets are noted for their loyal or playful characteristics, for their attractive appearance, or for their song. Pets also generally seem to provide their owners with non-trivial health benefits; keeping pets has been shown to help relieve stress. There is now a medically-approved class of therapy animals, mostly dogs, who are brought to visit confined humans. Walking a dog can provide both the owner and the dog with exercise, fresh air, and social interaction.

Koko the gorilla is one of few examples of a non-human animal which has had an explicit pet. Using sign language, she requested a cat; her first pet was a kitten named All Ball, to which she was reported to be quite attached and mourned for several days after the cat escaped and was killed by a car.

The GloFish is a genetically modified fluorescent zebrafish with bright red, green, and orange fluorescent color. It is the first genetically modified animal to become available as a pet.