The Atom :: Atoms Molecules Elements Science Essays

The Atom An atom is the smallest unit of matter that isrecognizable as a chemical ELEMENT. Atoms of antithetic elements may also combine into systemscalled MOLECULES, which are the smallest unitsof chemical COMPOUNDS. In all these ordinaryprocesses, atoms may be considered as theancient Greeks imagined them to be the ultimate edifice blocks of matter. When stronger forcesare applied to atoms, however, the atoms maybreak up into smaller parts. Thus atoms areactually composites and not units, and have acomplex inner organize of their own. By studyingthe processes in which atoms break up, scientistsin the 20th century have come to understand manydetails of the inner structure of atoms. The coat ofa typical atom is only about 10 (-10th) meters. Acubic centimeter of solid matter containssomething like 10 (24th) atoms. Atoms cannot beseen victimization optical microscopes, because they aremuch smaller than the wavelengths of visible light.By using more advanced imaging techniques suchas electron microscopes, scanning tunnelingmicroscopes, and atomic force microscopes,however, scientists have been able to produceimages in which the sites of individual atoms canbe identified. EARLY ATOMIC THEORIES Thefirst recorded speculations that MATTERconsisted of atoms are install in the works of theGreek philosophers LEUCIPPUS andDEMOCRITUS. The essence of their views isthat all phenomena are to be understood in termsof the motions, through empty space, of a large come up of tiny and indivisible bodies. (The nameatom comes from the Greek words atomos, forindivisible.) According to Democritus, thesebodies differ from one another in shape and size,and the observed variety of substances derivesfrom these differences in the atoms composingthem. Greek atomic theory was not an attempt toaccount for specific details of physical phenomena.It was instead a philosophical response to the top dog of how change can occur in reputation. Littleeffort was made to make atomic theoryquantitat ive--that is, to develop it as a scientific meditation for the study of matter. Greek atomism,however, did introduce the valuable concept thatthe nature of everyday things was to beunderstood in terms of an invisible substructure ofobjects with unfamiliar properties. Democritus say this especially clearly in one of the fewsayings of his that has been preserved Colorexists by convention, sweet by convention, bitterby convention, in reality zero exists but atomsand the void. Although adopted and extended bysuch later ancient thinkers as EPICURUS andLUCRETIUS, Greek atomic theory had strongcompetition from other views of the nature ofmatter. One such view was the four-elementtheory of EMPEDOCLES. These alternativeviews, championed by ARISTOTLE amongothers, were also motivated more by a desire toanswer philosophical questions than by a wish to