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Corundum
2005-05-26 11:05:25

Corundum is the crystalline form of aluminium oxide and one of the rock-forming minerals. Corundum is naturally clear, but can have different colors when impurities are added. Transparent specimens are used as gems, called ruby if red, while all other colors are called sapphire. The word corundum comes from the Hindi kurand. The oxygen atoms in corundum are arranged in a hexagonal...

Electromagnetic Spectrum
2004-10-19 04:45:41

Electromagnetic Spectrum -- The electromagnetic spectrum describes the various types of electromagnetic radiation based on their wavelengths. Radio, representing wavelengths from a few feet to well over a mile, is at one end of the spectrum. Gamma ray radiation is at the other end: the wavelength of the harder types is so short, in the subatomic range, that we do not have instruments...

Word of the Day
attercop
  • A spider.
  • Figuratively, a peevish, testy, ill-natured person.
'Attercop' comes from the Old English 'atorcoppe,' where 'atter' means 'poison, venom' and‎ 'cop' means 'spider.' 'Coppa' is a derivative of 'cop,' top, summit, round head, or 'copp,' cup, vessel, which refers to 'the supposed venomous properties of spiders,' says the OED. 'Copp' is still found in the word 'cobweb.'
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