Atoms ancient Greeks

In summary, for Leukipp and Demokrit, the empty space between the atoms was a key assumption in their model, because, if particles were closely packed, they could not move and substances could not be mixed. When asking students to philosophise about the nature of matter, we indeed find parallels to the ancient Greek thinking, both to the so-called atomists and to the continuous ideas of Aristotle and others. For example, Leukipp s and Demokrit s explanation for the specific weight of substances corresponds to one student conception younger students especially tend to explain differences in the specific weight (but also hardness of substances) with differences in the closeness of particles (Fig. 10.6). They seldom take into account that the particles could have a different weight themselves. 

In 1804, John Dalton proposed the existence of atoms. He not only postulated that atoms exist, as had ancient Greek philosophers, but he also attributed to the atoms certain properties. His postulates were as follows ... 

Why was Dalton s contribution different from that of the ancient Greeks who postulated the existence of atoms ... 

Rybach, L. and Nissen, H.U. (1964). Neutron activation of Mn and Na traces in marbles worked by the Ancient Greeks. In Proceedings of Radiochemical Methods of Analysis. International Atomic Energy Agency, Vienna, pp. 105-117. 

The idea that matter is made up of atoms was not new in Dalton s time. It was known to the ancient Greeks. Even in Robert Boyle s day the idea that matter was composed of particles, or corpuscles, of some kind was commonly believed. Dalton revolutionized chemistry, not by reintroducing this old idea but by formulating a workable theory of the formation of chemical compounds. 

People have been thinking about tiny objects for a long time. The ancient Greek philosopher Democritus (ca. 460-370 b.c.e.) believed that properties of matter depended on the shapes of small, indivisible bits of matter called atoms. Although this idea failed to catch on at the time— no one could see these atoms because they were so small—in 1803, the British chemist John Dalton (1766-1844) proposed a similar theory. Dalton s theory was an important advance and helped scientists understand chemical reactions—for example, the reaction of two atoms of hydrogen (H) and one atom of oxygen (O) to form H O—but atoms themselves remained cloaked in mystery. 

Al-Razi (Rhazes, 854-925) was a Persian who studied in Baghdad. Al-Razi wrote extensively on medicine, philosophy, astronomy, and alchemy, but he was primarily a physician. Al-Razi was less mystical than his contemporary alchemists and classified chemicals by their origin. According to Al-Razi, chemicals came from either animals, plants, and minerals or were derived from other chemicals. Al-Razi wrote The Comprehensive Book, which was an enormous medical encyclopedia that synthesized medical practices of ancient Greeks, Syrians, Arabs, and Persians. Al-Razi was the first person known to describe the disease smallpox. Most of his alchemical writings have been lost, but Al-Razi believed in the atomic nature of matter. Al-Razi took a systematic approach to science and rejected the idea of divine intervention. His rational methods and descriptions were more consistent with modern science than most individuals of his time. Ali al Husayn ibn Sina (Avicenna, 980-1037) was another Persian physician whose voluminous works, including The... 

In the classical era in Europe, the theory and practice of chemistry were pursued mainly by the ancient Greeks, who made many important discoveries in metallurgy in particular and who are also credited with proposing the earliest version of the atomic theory. The Greek chemical tradition declined when mysticism displaced the observational approach in the second century of the Common Era, and subsequently was largely lost in Europe after the fall of Rome in 410 c.E. In the 11th. century c.E., the quasiscience of alchemy returned to Europe via the Arabs, who also introduced Persian, Indian, and Chinese influences. 

There was one early hint at the modern way of thinking of elements, from the ancient Greek scholar Democritus (-460--370 b.c.), who thought that materials like fire were made up of tiny invisible particles that could not be broken into smaller pieces. The word he used for these particles is atomos. Atoms, as they are called today, are the particles that make up elements. The element gold is made up of gold atoms the element lead is made of lead atoms, and so on. 

Atom The word comes originally from the Greek word atomos, meaning uncut or indivisible. The ancient Greek philosophers known as the Epicureans believed that matter was composed on small, hard particles they called atomos. The idea and the word was revived in the 1600s to represent the smallest fundamental particle of matter. Today it means the smallest part of an element that can exist independently and interact chemically. 

The material world is made up of atoms, molecules and ions. The first reference to atoms can be found in the writings of the ancient Greeks. The first clear atomic hypothesis for the existence of atoms, was presented in 1805 by John Dalton. He suggested ... 

The third and final Greek contribution that we shall mention here is the notion of classification. The ancient Greeks were classifiers par excellence and classified everything from atoms to animals. In fact it was Aristotle who first attempted a classification of the various species of fauna [7]. The process of classification always involves the idea of similarity in this process objects that have at least some features in common, i.e. some similarity, are grouped together to form classes or categories. The process was explored in some detail in a book... 

Mixing these levels of terminology is difficult to avoid when the issue of smallest particles is introduced arising from the question of the division of a portion of matter is it possible to repeatedly and endlessly divide a piece of copper If the answer at the end of the discussion is that there are limits, then the result usually shows a smallest possible matter part. The ancient Greeks in Democritus circle spoke of atoms probably meaning the smallest indivisible part of matter. If one critically researches the earlier literature, one will probably also see many of our chemists and physicists transferring the well-known characteristics of matter to atoms or molecules. 

It is true that the ancient Greeks were concerned with knowledge for its own sake. They even had a well-developed atomic theory which was in many ways similar to atomic theory today. But the Greeks were not fond of doing experimental work, so their theory just stayed on the books and was never developed. 

Speculations about the nature of matter date back to ancient Greek philosophers like Thales, who lived in the sixth century b.c.e., and Democritus, who lived in the fifth century b.c.e., and to whom we credit the first theory of atoms. It has taken two and a half millennia for natural philosophers and, more recently, for chemists and physicists to arrive at a modern understanding of the nature of elements and compounds. By the 19th century, chemists such as John Dalton of England had learned to define elements as pure substances that contain only one kind of atom. It took scientists like the British physicists Joseph John Thomson and Ernest Rutherford in the early years of the 20th century, however, to demonstrate what atoms are—entities composed of even smaller and more elementary particles called protons, neutrons, and electrons. These particles give atoms their properties and, in turn, give elements their physical and chemical properties. 

The ancient Greek philosophers Leucippus and Democritus beheved that atoms existed, but they had no idea as to their nature. Centuries later, in 1803, the English chemist John Dalton, guided by the experimental fact that chemical elements cannot be decomposed chemically, was led to formulate his atomic theory. Dalton s atomic theory was based on the assumption that atoms are tiny indivisible entities, with each chemical element consisting of its own characteristic atoms. ... 

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