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Thunder Image
Thunder is the sound caused by lightning. Depending upon the distance from and nature of the lightning, it can range from a long, low rumble to a sudden, loud crack. The sudden increase in temperature and hence pressure caused by the lightning produces rapid Thermal expansion, expansion of the air in the path of a Lightning strike, lightning bolt. In turn, this expansion of air creates a Shock wave, sonic shock wave, often referred to as a "thunderclap" or "peal of thunder". The scientific study of thunder is known as ''brontology'' and the irrational fear (phobia) of thunder is called ''brontophobia''. Etymology The ''d'' in Modern English ''thunder'' (from earlier Old English ''þunor'') is epenthetic, and is now found as well in Modern Dutch ''donder'' (cf. Middle Dutch ''donre''; also Old Norse ''þorr'', Old Frisian ''þuner'', Old High German ''donar'', all ultimately descended from Proto-Germanic *''þunraz''). In Latin the term was ''tonare'' "to thunder". The name of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anvil Shaped Cumulus Panorama Edit Crop
An anvil is a metalworking tool consisting of a large block of metal (usually forged or cast steel), with a flattened top surface, upon which another object is struck (or "worked"). Anvils are as massive as practical, because the higher their inertia, the more efficiently they cause the energy of striking tools to be transferred to the work piece. In most cases the anvil is used as a forging tool. Before the advent of modern welding technology, it was the primary tool of metal workers. The great majority of modern anvils are made of cast steel that has been heat treated by either flame or electric induction. Inexpensive anvils have been made of cast iron and low quality steel, but are considered unsuitable for serious use as they deform and lack rebound when struck. Structure The primary work surface of the anvil is known as the face. It is generally made of hardened steel and should be flat and smooth with rounded edges for most work. Any marks on the face will be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
