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4/7/12

Behaviorism theory

Behaviorism theory
an essay to human psychology understanding


Behaviorism (or behaviourism), also called the learning perspective (where any physical action is a behavior), is a philosophy of psychology based on the proposition that all things that organisms do—including acting, thinking, and feeling—can and should be regarded as behaviors, and that psychological disorders are best treated by altering behavior patterns or modifying the environment.[1][2] The behaviorist school of thought maintains that behaviors as such can be described scientifically without recourse either to internal physiological events or to hypothetical constructs such as the mind.[3] Behaviorism comprises the position that all theories should have observational correlates but that there are no philosophical differences between publicly observable processes (such as actions) and privately observable processes (such as thinking and feeling).[4]
From early psychology in the 19th century, the behaviorist school of thought ran concurrently and shared commonalities with the psychoanalytic and Gestalt movements in psychology into the 20th century; but also differed from the mental philosophy of the Gestalt psychologists in critical ways.[5] Its main influences were Ivan Pavlov, who investigated classical conditioning although he did not necessarily agree with behaviorism or behaviorists, Edward Lee Thorndike, John B. Watson who rejected introspective methods and sought to restrict psychology to experimental methods, and B.F. Skinner who conducted research on operant conditioning.

4/6/12

Evolution theory

Evolution theory
explanation for the appearance of life and human beings on earth



Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.
Life on Earth originated and then evolved from a universal common ancestor approximately 3.7 billion years ago. Repeated speciation and the divergence of life can be inferred from shared sets of biochemical and morphological traits, or by shared DNA sequences. These homologous traits and sequences are more similar among species that share a more recent common ancestor, and can be used to reconstruct evolutionary histories, using both existing species and the fossil record. Existing patterns of biodiversity have been shaped both by speciation and by extinction.
Charles Darwin was the first to formulate a scientific argument for the theory of evolution by means of natural selection. Evolution by natural selection is a process that is inferred from three facts about populations: 1) more offspring are produced than can possibly survive, 2) traits vary among individuals, leading to differential rates of survival and reproduction, and 3) trait differences are heritable. Thus, when members of a population die they are replaced by the progeny of parents that were better adapted to survive and reproduce in the environment in which natural selection took place. This process creates and preserves traits that are seemingly fitted for the functional roles they perform. Natural selection is the only known cause of adaptation, but not the only known cause of evolution. Other, nonadaptive causes of evolution include mutation and genetic drift.

4/5/12

Theory of relativity

Theory of relativity


The theory of relativity, or simply relativity, encompasses two theories of Albert Einstein: special relativity and general relativity.The basic overall concept is that both time and space are relative, not fixed. However, the word relativity is sometimes used in reference to Galilean invariance.
The term "theory of relativity" was based on the expression "relative theory" (German: Relativtheorie) used by Max Planck in 1906, who emphasized how the theory uses the principle of relativity. In the discussion section of the same paperAlfred Bucherer used for the first time the expression "theory of relativity" (German:Relativitätstheorie).

big bang theory Scientific explanation for the beginning of the universe

big bang theory Scientific explanation for the beginning of the universe.


The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the Universe to cool and resulted in its present continuously expanding state. According to the most recent measurements and observations, the Big Bang occurred approximately 13.75 billion years ago,which is thus considered the age of the Universe. After its initial expansion from asingularity, the Universe cooled sufficiently to allow energy to be converted into varioussubatomic particles, including protons, neutrons, and electrons. While protons and neutronscombined to form the first atomic nuclei only a few minutes after the Big Bang, it would take thousands of years for electrons to combine with them and create the first atoms, the building blocks of matter. The first element produced was hydrogen, along with traces of helium andlithium. Giant clouds of these primordial elements would coalesce through gravity to form starsand galaxies, and the heavier elements would be synthesized either within stars or during supernovae.
The Big Bang is a well-tested scientific theory which is widely accepted within the scientific community because it is the most accurate and comprehensive explanation for the full range of phenomena astronomers observe. Since its conception, abundant evidence has arisen to further validate the model. Georges Lemaître first proposed what would become the Big Bang theory in what he called his "hypothesis of the primeval atom." Over time, scientists would build on his initial ideas to form the modern synthesis. The framework for the Big Bang model relies on Albert Einstein's general relativity and on simplifying assumptions (such ashomogeneity and isotropy of space). The governing equations had been formulated by Alexander Friedmann. In 1929 Edwin Hubble discovered that the distances to far away galaxies were generally proportional to their redshifts—an idea originally suggested by Lemaître in 1927. Hubble's observation was taken to indicate that all very distant galaxies and clusters have an apparent velocity directly away from our vantage point: the farther away, the higher the apparent velocity.