Definition of motor for English Language Learners : of, relating to, used in, or involving a vehicle that is powered by a motor (such as a car or motorcycle) : having a motor
Ancient Greeks and Romans used aluminum salts for dressing wounds. However, aluminum metal was not isolated until the 19th century. Danish chemist Hans Christian Ãrsted first produced aluminum in 1825 by reacting aluminum chloride with potassium amalgam. Therefore, Ãrsted is considered to be the discoverer of Aluminum.
Although aluminum is the most abundant metal in the earth's crust, it is never found free in nature. All of the earth's aluminum has combined with other elements to form compounds. Two of the most common compounds are alum, such as potassium aluminum sulfate (KAl(SO4)2Â·12H2O), and aluminum oxide (Al2O3). About 8.2% of the earth's crust is composed of aluminum. Scientists suspected than an unknown metal existed in alum as early as 1787, but they did not have a way to extract it until 1825.