Schrödinger equation

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Schrödinger equation, developed by the Austrian physicist Erwin Schrödinger in 1925, is a fundamental equation in quantum mechanics. It describes the evolution over time of a massive non-relativistic particle, and thus fulfills the same role as the fundamental relation of … Read More

Scientific laws

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A scientific law is a scientific proposition that affirms a constant relationship between two or more variables or factors, each of which represents a property or measurement of specific systems. It is also defined as a constant and invariable rule and norm of things, arising from its first cause or its qualities and conditions. It … Read More

Propositional logic

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Propositional logic (propositional calculus, statement logic, sentential calculus, sentential logic, or sometimes zeroth-order logic) is part of the mathematical logic. Its purpose is the study of the logical relations between “propositions” and defines the formal laws according to which the … Read More

Special theory of relativity

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Special Theory of Relativity (or Special relativity) is the formal theory elaborated by Albert Einstein in 1905 in order to draw all the physical consequences of Galilean relativity and the principle according to which the speed of light in a … Read More

Scientific instruments

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A scientific instrument is an instrument used in science to acquire data, from nanoscale to macroscopic scales. These are mostly measuring instruments (spectrometer for example) or observation (polarizing microscope for example) or, more and more, both at once. Characterizations An … Read More

Atom

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(Representation of a helium-4 atom with, appearing pink in the center, the atomic nucleus and, in gradient of gray all around, the electronic cloud. The helium-4 nucleus, enlarged on the right, is formed of two protons and two neutrons.) An … Read More

Taxonomies

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(Phylogenetic trees have the shape of dendrograms, each node of the dendrogram corresponds to a clade. ) Taxonomy (from the Greek: ταξις, taxis, ordering and νομος, nomos, norm or rule) is, in its most general sense, the discipline of classification. … Read More

Optics

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(Optics includes study of dispersion of light. ) Optics is the branch of electromagnetism that describes the behavior and properties of light and its interaction with matter (photometry). The perspective deals with what are called the optical phenomena, on the … Read More

Natural philosophy

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Natural philosophy, known in Latin as philosophia naturalis, is an expression that applied to the objective study of nature and the physical universe that reigned before the development of modern science. Traditionally allied with natural theology, it used to designate … Read More

Electrostatics

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(Lightning causing a flash of light over Oradea in Romania.) Electrostatics is the branch of physics that studies the phenomena created by static electric charges for the observer. The obtained laws can be generalized to variable (quasi-electrostatic) systems provided that … Read More

Phenomena

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(Cloud chamber phenomena. Scientists use phenomena to refine some hypotheses and sometimes to disprove a theory. ) A phenomenon is the way in which a thing, a fact of the physical world (object, action …), psychic (emotion, thought …) or … Read More

Vibrations

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A vibration is a mechanical oscillation motion around a stable equilibrium position or an average trajectory. The vibration of a system can be free or forced. According to the type and nature of vibration, and according to the measuring means, … Read More