Tuesday, October 30, 2007

Biography

Biography is a type of literature and further forms of media such as film, based on the written accounts of individual lives. While a biography may focus on a subject of fiction or non-fiction, the term is frequently in reference to non-fiction. Pat Shipman however, says "I think a good biographer has to write fiction some of the time to make apparent a significant event in someone's life." This is sometimes debated. As opposed to a profile or curriculum vitae, a biography develops a complex analysis of personality, highlighting different aspects of it and including intimate details of experiences. A biography is more than a list of distant facts like birth, education, work, relationships and death. It also delves into the emotions of experiencing such events.

Ancient Greeks developed the biographical tradition which we have inherited, although until the 5th century AD, when the word biographia first appears, in Damascius Life of Isodorus , biographical pieces were called simply "lives". It is quite likely that the Greeks were drawing on a pre-existing eastern tradition; certainly Herodotus' Histories contains more exhaustive biographical information on Persian kings and subjects than on anyone else, implying he had a Persian source for it.

Monday, October 22, 2007

Calculator

A calculator is a machine for performing calculations. Although modern calculators often incorporate a general purpose computer, the device is calculated for performing specific operations, rather than for flexibility. Modern calculators are more convenient than most computers, though some Pads are comparable in amount to handheld calculators.

In the past, some calculators were as huge as today's computers. The first automatic calculators were mechanical desktop devices which were replaced by electromechanical desktop calculators, and then by electronic devices using first sung valves, then transistors, then hard-wired integrated circuit logic. New calculators are electrically powered and come in innumerable shapes and sizes varying from cheap, give-away, credit-card sized models to more sturdy adding machine-like models with built-in printers.

Friday, October 12, 2007

Rainbows

Rainbows can be practical whenever there are water drop in the air and sunlight shining from behind the observer at a low altitude or angle. The most spectacular rainbow displays when half of the sky is still dim with draining clouds and the observer is at a spot with clear sky overhead. The rainbow effect is also commonly seen near waterfalls or fountains. Rainbow fringes can sometimes be seen at the edges of backlit clouds and as vertical bands in far rain or virga. The effect can also be artificially created by dispersing water droplets into the air during a sunny day. Rarely, a moonbow, lunar rainbow or night-time rainbow, can be seen on stoutly moonlit nights. As human visual observation for colour is poor in low light, moonbows are most often perceived to be white.
The rainbow's exterior is caused by dispersion of sunlight as it goes through raindrops. The light is first refracted as it enters the surface of the raindrop, reflected off the back of the drop, and over refracted as it leaves the drop. The overall effect is that the incoming light is reflected back over a wide range of angles, with the most intense light at an angle of 40°–42°. The angle is self-determining of the size of the drop, but does depend on its refractive index. Seawater has a higher refractive index than rain water, so the radius of a 'rain'bow in sea spray is smaller than a true rainbow. This is visible to the naked eye by a misalignment of these bows.