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Arrow pushing or electron pushing is a technique used to describe the progression of organic chemistry reaction mechanisms. [1] It was first developed by Sir Robert Robinson . In using arrow pushing, "curved arrows" or "curly arrows" are drawn on the structural formulae of reactants in a chemical equation to show the reaction mechanism .
A silver Peruvian atlatl from the 12th-15th century Atlatl in use. A spear-thrower, spear-throwing lever, or atlatl (pronounced / ˈ æ t l æ t əl / ⓘ [1] or / ˈ ɑː t l ɑː t əl /; [2] Nahuatl ahtlatl [ˈaʔt͡ɬat͡ɬ]) is a tool that uses leverage to achieve greater velocity in dart or javelin-throwing, and includes a bearing surface that allows the user to store energy during the ...
A Swiss arrow [1] (also known as a Yorkshire arrow, Dutch arrow, Scotch arrow, or Gypsy arrow) is a type of enlarged dart in the shape of an arrow that is thrown with the aid of a lanyard, which is retained by a small notch close to the fletching. It is very similar to an amentum and uses the same throwing principle as a spear-thrower.
Spear-thrower or atlatl, a tool that uses leverage to achieve greater velocity in dart-throwing, and includes a bearing surface which allows the user to store energy during the throw; Woomera (spear-thrower), a wooden Australian Aboriginal spear-throwing device similar to an atlatl
Depending on your height, you'll want to use a dart that's about a foot taller than you are for better accuracy. Using an atlatl can be easy. Hitting a target is another story.
In these experiments, the total current passed is measured directly or indirectly to determine the number of electrons passed. Knowing the number of electrons passed can indicate the concentration of the analyte or when the concentration is known, the number of electrons transferred in the redox reaction.
A woomera is an Australian Aboriginal wooden spear-throwing device. [1] [2] [3] Similar to an atlatl, it serves as an extension of the human arm, enabling a spear to travel at a greater speed and force than possible with only the arm.
Microliths were also used from the Neolithic on arrows, although a decline in this use coincided with the appearance of bifacial or "leafed" arrowheads that became widespread in the Chalcolithic period, or Copper Age (that is, stone arrowheads were increasingly made by a different technique during this later period).