Pole

The poles of the Earth, or other planet, are the points where its axis of rotation passes through its surface, e.g.: North Pole, South Pole. A magnetic pole of a planet is the pole of its planetary magnetic field, if it exists.

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A pole is a long and straight stick, usually vertical or intended to be used vertically. See barber, pole vault.

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In complex analysis, a pole of a function is a certain simple type of singularity. See pole (complex analysis).

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A pole is also a unit of length, also called a rod, equal to 5.5 yards or 16.5 feet (5.029 meters in SI units).

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Pole is also a term for the people of Poland. See demographics of Poland.

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In chemistry, a polar molecule is one that has concentrations of positive or negative electric charge. A commonly-used example of a polar compound is water (H₂O). It has the structure

    O
  H   H

The electrons of the hydrogen atoms are strongly attracted to the oxygen atom, and are actually closer to its nucleus than to those of the hydrogens. Thus, the molecule has a strong negative charge in the middle, and a positive charge at the ends.

Polar compounds are only soluble in other polar compounds.

See also: nonpolar, hydrophilic