The nature of matter

Matter Atoms Compounds Molecule Elements Solid Liquid Gas 

The surface of the copper penny is made of copper atoms represented as they would be seen through the lens of a very powerful electronic microscope. 

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A scanning tunneling microscope image of nickel metal. Each peak represents a nickel atom. 

The profile of radiation emitted from a blackbody. Note that the maximum shifts to shorter wavelengths as the temperature is increased, in agreement with the observed change from a reddish to a white glow as iron is heated to higher temperatures. 

Energy can be gained or lost only in integer multiples of hr. 

It is probably fair to say that at the end of the nineteenth century physicists were feeling rather smug. Available theories could explain phenomena ranging from the motions of the planets to the dispersion of visible light by a prism. Rumor has it that students were being discouraged from pursuing physics as a career because it was believed that all the major problems had been solved or at least described in terms of the current physical theories. 

Planck found that the observed profiles (with their intensity maxima) could be accounted for by postulating that energy can be gained or lost only in whole-number multiples of the quantity hv, where h is a constant now called Planck s constant, determined by experiment to have the value 6.626 X 10 34 J s. That is, the change in energy for a system AE can be represented by the equation 

CuCI produces a blue flame when heated in 

IBLG See questions from The Nature of Matter and the Atomic Spectrum of Hydrogen  

The briUiant red colors seen in fireworks are due to the emission of light with wavelengths around 650 nm when strontium salts such as Sr(NOs)2 and SrCOs are heated. (This can be easily demonstrated in the lab by dissolving one of these salts in methanol that contains a little water and igniting the mixture in an evaporating dish.) Calculate the frequency of red light of wavelength 6.50 X 10 nm. 

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When a strontium salt is dissolved in methanol (with a little water) and ignited, it gives a brilliant red flame. The red color is produced by emission of light when electrons, excited by the energy of the burning methanol, fall back to their ground states. 

At the beginning of the twentieth century, however, certain experimental results suggested that this picture was incorrect. The first important advance came in 1900 from the German physicist Max Planck (1858-1947). Studying the radiation profiles emitted by solid bodies heated to incandescence, Planck found that the results could not be explained in terms of the physics of his day, which held that matter could absorb or emit any quantity 

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The concept that all substances are composed of elements and atoms goes back at least 2000 years. Originally, only four elements were recognized air, earth, fire, and water. Each substance was thought to consist of very small particles, called atoms, that could not be subdivided any further. This early mental concept of the nature of matter was extremely prescient, considering there were no experimental results to indicate that matter should be so and none to verify that it was so. Modern atomic theory is much more rigorously based, and we even have the ability to see atoms with special tunneling microscopes. All of chemistry is based on how atoms react with each other. 

The initial set of experiments and the first few textbook chapters lay down a foundation for the course. The elements of scientific activity are immediately displayed, including the role of uncertainty. The atomic theory, the nature of matter in its various phases, and the mole concept are developed. Then an extended section of the course is devoted to the extraction of important chemical principles from relevant laboratory experience. The principles considered include energy, rate and equilibrium characteristics of chemical reactions, chemical periodicity, and chemical bonding in gases, liquids, and solids. The course concludes with several chapters of descriptive chemistry in which the applicability and worth of the chemical principles developed earlier are seen again and again. 

Novick, S., Nussbaum, J. (1981). Pupils understanding of the nature of matter A cross age study. 

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. 

Scientists and science writers did not merely turn to occult notions to help describe or even inspire their research. As Modem Alchemy demonstrates, during the period from the turn of the century to just before World War II, the trajectories of science and occultism briefly merged. The stories told here document how and why the nature of matter was so newly important to both scientists and occultists—and they uncover the spiritual and ethical implications of the new material science of radioactivity. 

Occultists, then, increasingly focused on alchemy as a material science validated by the new atomic chemistry and physics, even if it was a science with spiritual implications. Many occult phenomena now began to be explained in terms of radiation and material particles as occultists turned to scientists to validate their belief.6 Never had modem occultism been so much concerned with the nature of matter—that is, the nature of material change. To understand this development in the relationship between occultism and material science, we must first briefly rehearse the history of the broad occult movement beginning half a century earlier. 

Ernest Rutherford, Frederick Soddy, and then Sir William Ramsay documented natural transformations of one element into another in 1902 and 1903. The artificial transmutation of one element into another, however, was first accomplished in 1919 by Rutherford, a physicist. Indeed, the field of nuclear physics has contributed the most to our understanding of the subatomic world since the 1920s. But the scientists who most advocated transmutation as a goal of research and a heuristic principle for understanding the nature of matter—the Nobel Prize winners Ramsay and Soddy, and, in a less prominent way, Sir William Crookes—were chemists, not physicists.1... 

The pulp sci-fi stories published in the Gernsback periodicals during the Depression track how economic and monetary anxieties dovetailed with the stunning rethinking of the nature of matter that the previous three decades had styled as modern alchemy. Indeed, the stories affirm that ... 

Brock, William H. 1985. From Protyle to Proton William Prout and the Nature of Matter, 1785-1985. Bristol and Boston Adam Hilger. 

You have seen how scientists in the late nineteenth and early twentieth century developed and modified the atomic model. Changes in this model resulted from both experimental evidence and new ideas about the nature of matter and energy. By 1913, chemists and physicists had a working model that pointed tantalizingly in a promising direction. During the third decade of the twentieth century, the promise was fulfilled. In the next section, you will learn how physicists extended the ideas of Planck, Einstein, and Bohr to develop an entirely new branch of physics, and a new model of the atom. 

Over the centuries, many other concepts were proposed to explain the nature of matter— many of them extensions of the Greek concept of an ultimately indivisible and indestructible elementary bit of matter. But it was not until J. J. Thomson proposed his model of the atom, consisting of a sphere with an agglomeration of particles with negative electric charges somehow positioned randomly inside a very small ball of matter, that the modern structure of the atom began to take shape. 

Hehum is used for low-temperature research (—272.2°C or 34°F). It has become important as a coolant for superconducting electrical systems that, when cooled, oiler httle resistance to the electrons passing through a conductor (wire or magnet). When the electrons are stripped from the hehum atom, a positive He ion results. The positive hehum ions (nuclei) occur in both natural and man-made radioactive emissions and are referred to as alpha particles. Hehum ions (alpha particles) are used in high-energy physics to study the nature of matter. 

Thus it was the physicists who took the next steps toward understanding the nature of matter. In 1896 the French physicist Henri Becquerel discovered radioactivity, and in 1897 the English physicist J. J. Thomson discovered the first subatomic particle, the electron. Subsequently, studies of the radiation emitted by radioactive atoms showed that these atoms emitted radiation of three different kinds, which were called alpha, beta, and gamma after the first three letters... 

Once Nature has been transcended, then, says Steiner (just as did Kandinsky ), for the first time, large numbers of people will feel spiritual life to be a vital necessity, when [through Art] spiritual life and practical life are finally brought into direct connection with each other. Because [only] Spiritual-Occult Science [die geheime Wissensdwft, or Secret Science ] is able to throw light on the nature of matter, so will Art, which is bom of Spiritual-Occult Science, attain to the power of giving direct form to every chair, every table, to every man-created object. 

By 1780, a number of different types of airs had been isolated and discoveries made that raised serious questions about the nature of matter. Air, earth, and water were shown to be compounds and mixtures rather than the basic elements from ancient times. 

In the Sarvastivadin school of Buddhism (-400 BCE), the minimum indivisible particle of matter was called the atom, which expresses the nature of matter. The characteristic atoms were earth (sohd), water (liquid), fire (heat), air (moving), color, taste, odor, and sense of touch, and they existed in space. The smallest composite unit was considered to be composed of seven characteristic atoms, which are set at the apices and center of octahedron (S). 

The later chemistry, however, was the product of the influences of these practical chemical arts, combined with the mysticism of Asiatic or Egyptian origin, and the philosophy of the East and of Greece, respecting the nature of matter and the elements which impart to it its varying forms and properties. 

Though the writers upon whose works we are mainly dependent for our knowledge of practical chemistry have little to say of the prevalent theories of matter, yet from other sources we know that speculations on such subjects have earnestly occupied the minds of men since the earliest period of recorded philosophy. Especially in the earliest records of India and of Greece are met serious efforts to account for the origin and changes of the material universe by consistent theories of the nature of matter and its changes. 

Plato (427-347 B.C.), the great idealistic philosopher of Athens, and for some eight years the pupil of Socrates, contributed little of permanent influence in the specific doctrines of the nature of matter and its changes. Adopt-... 

Aristotle s views on the nature of matter made so much sense to people that less obvious views were difficult to accept. One alternative view was the forerunner of our present-day model matter is composed of a finite number of incredibly small but discrete units we call atoms. This model was advanced by several Greek philosophers, including Democritus (460—370 B.c.), who coined the term atom from the Greek phrase a tomos, which means not cut or that which is indivisible. According to the atomic model of Democritus, the texmre, mass, and color of a material were a function of the texture, mass, and color of its atoms, as illustrated in Figure 3.2. So compelling was Aristotle s reputation, however, that the atomic model would not reappear for 2000 years. 

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