Tuesday, December 26, 2006

Economics

Economics is a social science seeking to analyze and describe the production, distribution, and consumption of goods and services. Economics studies how individuals and societies seek to satisfy needs and wants. Alfred Marshall in the late 19th century informally described economics as "the study of man in the ordinary business of life"; the vast number of topics to which the methods of economic theory have been applied suggests to some that economics is simply "that which economists do."

Economics has two broad branches: microeconomics, where the unit of analysis is the individual agent, such as a household or firm, and macroeconomics, where the focus is on aggregates, the sum of the supply and demand in an economy, or the total net result of buying and selling. Another division of the subject distinguishes positive economics, which seeks to predict and explain economic phenomena, from normative economics, which orders choices and actions by some criterion; such orderings necessarily involve subjective value judgments.

Monday, December 18, 2006

Tornado

A tornado is a violently rotating column of air which is in contact with both a cumulonimbus cloud base and the surface of the earth. Tornadoes can come in many shapes, but are typically in the form of a visible condensation funnel, with the narrow end touching the earth. Often, a cloud of debris encircles the lower portion of the funnel.

Tornadoes can be the most destructive storms on earth. Most have winds of 110 mph or less, are approximately 250 feet across, and travel a mile or more before dissipating. However, some tornadoes can have winds of more than 300 mph be more than a mile across, and stay on the ground for dozens of miles.

They have been observed on every continent except Antarctica; however, a significant percentage of the world's tornadoes occur in the United States. This is mostly due to the unique geography of the country, which allows the conditions which breed strong, long-lived storms to occur many times a year. Other areas which often experience tornadoes are south-central Canada, northwestern Europe, east-central South America, South Africa, and south-central Asia.

Wednesday, December 13, 2006

Greek temple

The Greeks began to build massive temples in the first half of the 8th century BC. The temples of Hera at Samos and of Poseidon at Isthmia were among the first erected. Greek temples differed from their Roman counterparts in that the colonnade shaped a peristyle around the whole structure, rather than merely a porch at the front; and also in that the Greek temple was not raised above ground level on a high podium.

As the Greeks became more adept at massive building, regional styles of architecture solidified into what are now the classical orders of architecture: Doric, Ionic and Corinthian. The Parthenon, one of the most famous Greek temples, was devoted to Athena, goddess of wisdom. Festivals were held in and around it every year. The Parthenon powerfully influenced Roman architecture. After the Romans conquered Greece, many tourists from the victorious country came to view the temples of Greece. Among them was the Parthenon, which rapidly became one of the most popular tourist sites in Greece. Unlike modern places of worship, Greek temples were not intended for group worship, but more as a dedication to a god or goddess, explaining why the sculpture on temples was always right at the top and hard to see - it was built for the pleasure of its deity and not for people.