Search results
Results From The WOW.Com Content Network
Thomson further explained that ions are atoms that have a surplus or shortage of electrons. [51] Thomson's model is popularly known as the plum pudding model, based on the idea that the electrons are distributed throughout the sphere of positive charge with the same density as raisins in a plum pudding. Neither Thomson nor his colleagues ever ...
First to explain the effects of Brownian motion as caused by the kinetic energy (i.e., movement) of atoms, which was subsequently, experimentally verified by Jean Baptiste Perrin, thereby settling the century-long dispute about the validity of John Dalton's atomic theory. 1905: Albert Einstein: Published his Special Theory of Relativity. 1905
Atomism (from Greek ἄτομον, atomon, i.e. "uncuttable, indivisible") [1] [2] [3] is a natural philosophy proposing that the physical universe is composed of fundamental indivisible components known as atoms. References to the concept of atomism and its atoms appeared in both ancient Greek and ancient Indian philosophical traditions.
Atoms can attach to one or more other atoms by chemical bonds to form chemical compounds such as molecules or crystals. The ability of atoms to attach and detach from each other is responsible for most of the physical changes observed in nature. Chemistry is the science that studies these changes.
At the start of the 20th century, the vigorous debate as to the existence of atoms had not yet been resolved. Philosophers such as Ernst Mach and Wilhelm Ostwald denied that atoms were real, viewing them as a convenient mathematical construct, while scientists such as Arnold Sommerfeld and Ludwig Boltzmann saw that physical theories required the existence of atoms.
The prevailing model of atomic structure before Rutherford's experiments was devised by J. J. Thomson. [2]: 123 Thomson had discovered the electron through his work on cathode rays [3] and proposed that they existed within atoms, and an electric current is electrons hopping from one atom to an adjacent one in a series.
In a more concrete manner, however, the concept of aggregates or units of bonded atoms, i.e. "molecules", traces its origins to Robert Boyle's 1661 hypothesis, in his famous treatise The Sceptical Chymist, that matter is composed of clusters of particles and that chemical change results from the rearrangement of the clusters.
Leucippus said that the cosmos was created when a large group of atoms came together and swirled as a vortex. They shifted around each other until they were sorted "like to like". The larger atoms gathered in the center while the smaller ones were pushed to the edge. The smaller atoms became the celestial bodies of the cosmos.