Monday, June 16, 2008


A watch is a timepiece that is made to be worn on a person, as different to a clock which is not. The term now generally refers to a wristwatch, which is worn on the wrist with a strap or bracelet. In addition to the time, modern watches often display the day, date, month and year, and electronic watches may have many other facilities.

Most low-cost and medium-priced watches used mainly for timekeeping are electronic watches with quartz movements. Luxurious, collectible watches valued more for their workmanship and aesthetic appeal than for simple timekeeping, often have purely mechanical movements and are powered by springs, even though mechanical movements are less accurate than more affordable quartz movements.

Before the low-cost miniaturization that became possible in the 20th century, most watches were pocket watches, which had covers and were carried in a pocket and attached to a watch chain or watch fob. Watches evolved in the 1600s from spring
power-driven clocks, which appeared in the 1400s.

Sunday, June 08, 2008

Water Pollution

Water pollution is the contamination of water bodies such as lakes, rivers, oceans, and groundwater caused by human behavior, which can be harmful to organisms and plants which live in these water bodies.

Even though natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major changes in water quality and the ecological status of water, water is naturally referred to as polluted when it impaired by anthropogenic contaminants and either does not support a human use (like serving as drinking water) or undergoes a marked shift in its ability to support its constituent biotic communities. Water pollution has many causes and uniqueness. The main sources of water pollution are generally grouped into two categories based on their point of origin. Point-source pollution refers to contaminants that enter a waterway through a discrete "point source". The second primary category, non-point source pollution, refers to contamination that, as its name suggests, does not create from a single discrete source.

Halloween Costumes