Science (from the Latin word scientia, meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
The earliest roots of science can be traced to Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age. The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived "natural philosophy", which was later transformed by the Scientific Revolution that began in the 16th century as new ideas and discoveries departed from previous Greek conceptions and traditions. The scientific method soon played a greater role in knowledge creation and it was not until the 19th century that many of the institutional and professional features of science began to take shape; along with the changing of "natural philosophy" to "natural science."
Modern science is typically divided into three major branches that consist of the natural sciences (e.g., biology, chemistry, and physics), which study nature in the broadest sense; the social sciences (e.g., economics, psychology, and sociology), which study individuals and societies; and the formal sciences (e.g., logic, mathematics, and theoretical computer science), which study abstract concepts. There is disagreement, however, on whether the formal sciences actually constitute a science as they do not rely on empirical evidence. Disciplines that use existing scientific knowledge for practical purposes, such as engineering and medicine, are described as applied sciences.
Science is based on research, which is commonly conducted by scientists working in academic and research institutions, government agencies, and companies. The practical impact of scientific research has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the development of commercial products, armaments, health care, public infrastructure, and environmental protection. (Full article...)
The Aberfan disaster
was the catastrophic collapse of a colliery spoil tip
on 21 October 1966 in Wales
. The tip had been created on a mountain slope above the village of Aberfan
, near Merthyr Tydfil
, and overlaid a natural spring. A period of heavy rain led to a build-up of water within the tip leading to 'liquefaction', causing it to suddenly slide downhill as a slurry
, killing 116 children and 28 adults as it engulfed Pantglas Junior School and other buildings. The tip was the responsibility of the National Coal Board
(NCB), and the subsequent inquiry
placed the blame for the disaster on the organisation and nine named employees.
There were seven spoil tips on the slopes above Aberfan; Tip 7—the one that slipped onto the village—was begun in 1958 and, at the time of the disaster, was 111 feet (34 m) high. In contravention of the NCB's official procedures, the tip was partly based on ground from which water springs emerged. After three weeks of heavy rain the tip was saturated and approximately 140,000 cubic yards (110,000 m3
) of spoil slipped down the side of the hill and onto the Pantglas area of the village. The main building hit was the local junior school
, where lessons had just begun; 5 teachers and 109 children were killed in the school. (Full article...
Cartoon representation of a proteasome. Its active sites are sheltered inside the tube (blue). The caps (red; in this case, 11S regulatory particles) on the ends regulate entry into the destruction chamber, where the protein is degraded.
Credit: Blaise Frazier
A plasma globe is usually a clear glass orb, filled with a mixture of various inert gases at low pressure, and driven by high frequency alternating current at high voltage (approx. 35 kHz, 2–5 kV,15.7 Krem), generated by a high voltage transformer. A much smaller orb in its center serves as an electrode. Beams or snakes of "light" (actually emergent patterns in ionized gas) extend from the inner electrode to the outer glass container, giving an appearance similar to multiple constant beams of coloured lightning. The beams first follow the electric field lines of the dipole, but move up due to convection.
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(August 11, 1818 – June 28, 1889) was an American astronomer
. Born on Nantucket Island
, she was a first cousin four times removed of Benjamin Franklin
Her parents were Quakers who, unconventionally for their time, insisted on giving her the same quality of education that boys received. She worked as a librarian and also pursued astronomy at her father's observatory.
Using a telescope, she discovered "Miss Mitchell's Comet" (Comet 1847 VI, modern designation is C/1847 T1) in the autumn of 1847. Some years previously, King Frederick VI of Denmark had established gold medal prizes to each discoverer of a "telescopic comet" (too faint to be seen with the naked eye). The prize was to be awarded to the "first discoverer" of each such comet (note that comets are often independently discovered by more than one person). She duly won one of these prizes, and this gave her worldwide fame, since the only previous woman to discover a comet had been Caroline Herschel.
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