Chemistry (from Egyptian kme (chem), meaning 'earth') is the science that studies matter at the atomic to macromolecular scale, the reactions, transformations and aggregations of matter, as well as the energy and entropy released or absorbed during these processes. In short, chemistry studies molecules, crystals, and metals and is concerned with the composition and statistical properties of such structures, as well as their transformations and interactions to become materials encountered in everyday life. According to modern chemistry, the physical properties of materials are generally determined by their structure at the molecular or atomic scale, which is itself defined by interatomic electromagnetic forces, and laws of quantum mechanics and thermodynamics. Robert Boyle (1661), Antoine Lavoisier (1787), and John Dalton (1808) can be considered the three fathers of modern chemistry, although other scientists have played a vastly important role, such as Dmitri Mendeleyev, Friedrich Woehler, and Hermann Staudinger, to name but a few.
Wikipedia
Week From Wikipedia, the free encyclopedia Jump to: navigation, search For more details on each day of the week, see days of the week. For the TV station in the Peoria-Bloomington, Illinois market, see WEEK-TV. A week is a unit of time longer than a day and shorter than a month. In most modern calendars, including the Gregorian calendar, the week is a period of seven days. Contents 1 The week as indicator of market day 2 Origin of the seven-day week 2.1 Hindu, Babylonian, and Jewish seven-day week 2.2 Chinese seven-day week 3 Later use of the week
Wikipedia
Chemistry Week
E-Cards - Send Chemistry Week Greeting Card!
Send An E-Card For
Any Occasion
flashgreetingscards.com 2006 ©
All Rights Reserved free greeting cards Free
eCards
|
|
|
|
