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Meissner effect

Meissner effect

Science is the methodical study of nature including testable explanations and predictions. From classical antiquity through the 19th century, science as a type of knowledge was more closely linked to philosophy than it is now and, in fact, in the Western world, the term "natural philosophy" encompassed fields of study that are today associated with science, such as astronomy, medicine, and physics. However, during the Islamic Golden Age foundations for the scientific method were laid by Ibn al-Haytham in his Book of Optics. While the classification of the material world by the ancient Indians and Greeks into air, earth, fire and water was more philosophical, medieval Middle Easterns used practical, experimental observation to classify materials.

Today, the ever-evolving term "science" refers to the pursuit of knowledge, not the knowledge itself. It is often synonymous with "natural and physical science" and often restricted to those branches of study relating to the phenomena of the material universe and their laws. Although the term implies exclusion of pure mathematics, many university faculties include Mathematics Departments within their Faculty of Science. The dominant sense in ordinary use has a narrower use for the term "science." It developed as a part of science becoming a distinct enterprise of defining the "laws of nature"; early examples include Kepler's laws, Galileo's laws, and Newton's laws of motion. In this period it became more common to refer to natural philosophy as "natural science." Over the course of the 19th century, the word "science" became increasingly associated with the disciplined study of the natural world, including physics, chemistry, geology and biology. This sometimes left the study of human thought and society in a linguistic limbo, which was resolved by classifying these areas of academic study as social science. For example, psychology evolved from philosophy, and has grown into an area of study.

Currently, there are both "hard" (e.g. biological psychology) and "soft" science (e.g. social psychology) fields within the discipline. As a result, and as is consistent with the unfolding of the study of knowledge and development of methods to establish facts, each area of psychology employs a scientific method. Reflecting the evolution of the development of knowledge and established facts and the use of the scientific method, Psychology Departments in universities are found within: Faculty of Arts and Science, Faculty of Arts, and a Faculty of Science. Similarly, several other major areas of disciplined study and knowledge exist today under the general rubric of "science", such as formal science and applied science.

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Nanodevice that efficiently produces visible light, through energy transfer from quantum wells to quantum dots.
A quantum dot is a semiconducting crystal in nanotechnology. Quantum dots confine electrons, holes, electron-hole pairs, or excitons to zero dimensions in a region of the order of the electrons' Compton wavelength. This confinement leads to discrete quantized energy levels and to the quantization of charge in units of the elementary electric charge e. Quantum dots are particularly significant for optical applications due to their theoretically high quantum yield. Quantum dots have also been suggested as implementations of a qubit for quantum information processing.

Because the quantum dot has discrete energy levels, much like an atom, they are sometimes called artificial atoms. The energy levels can be controlled by changing the size and shape of the quantum dot, and the depth of the potential. Like in atoms, the energy levels of small quantum dots can be probed by optical spectroscopy techniques. In contrast to atoms it is relatively easy to connect quantum dots by tunnel barriers to conducting leads, which allows the application of the techniques of tunneling spectroscopy for their investigation.

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Wake Vortex Study at Wallops Island
Credit: NASA Langley Research Center (NASA-LaRC)

Wake turbulence, also known as "jetwash", is turbulence that forms behind an aircraft as it passes through the air. This turbulence can be especially hazardous during the landing and take off phases of flight, where an aircraft's proximity to the ground makes a timely recovery from turbulence-induced problems unlikely. Wingtip vortices make up the primary and most dangerous component of wake turbulence, but normal wake effects are also an important part. A method of reducing wingtip vortices employs the use of winglets.

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Gregor Mendel (1822–1884) was an Austrian monk who is often called the "father of genetics" for his study of the inheritance of traits in pea plants. Mendel showed that there was particular inheritance of traits according to his laws of inheritance.

It was not until the early 20th century that the importance of his ideas was realized. In 1900, his work was rediscovered by Hugo de Vries, Carl Correns, and Erich von Tschermak. His results were quickly replicated, and genetic linkage quickly worked out. Biologists flocked to the theory, as while it was not yet applicable to many phenomena, it sought to give a genotypic understanding of heredity which they felt was lacking in previous studies of heredity which focused on phenotypic approaches.

Did you know...


  • ...that Scientists and Engineers for America is an organization focused on promoting sound science in government, and backing political candidates who support science and its applications?
  • ...that walking fish can actually skip, crawl, slither, and even climb trees?

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