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Science, in the broadest sense of the term, refers to any system of knowledge attained by verifiable means. In a more restricted sense, science refers to a system of acquiring knowledge based on empiricism, experimentation, and methodological naturalism, as well as to the organized body of knowledge humans have gained by such research.

Scientists maintain that scientific investigation must adhere to the scientific method, a process for properly developing and evaluating natural explanations for observable phenomena based on empirical study and independent verification. Science, therefore, avoids supernatural explanations until all other natural possibilities have been considered, and rejects arguments from authority.

Fields of science are commonly classified along two major lines: Natural sciences, which study natural phenomena; and Social sciences, which study human behavior and societies. Whether mathematics is a science is a matter of perspective.

Fields of science can be further distinguished as pure science or applied science. Pure science is principally involved with the discovery of new truths with less (or no) regard to their applications. Applied science is principally involved with the application of existing knowledge in new ways.

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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 nanotechnology. Quantum dots confine electrons, holes, electron-hole pairs, or excitons to zero dimensions to a region on 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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A Tesla coil lightning simulator
Credit: Fir0002

A Tesla coil is a category of disruptive discharge transformer coils, named after their inventor, Nikola Tesla. Tesla coils are composed of coupled resonant electric circuits. Nikola Tesla actually experimented with a large variety of coils and configurations, so it is difficult to describe a specific mode of construction that will meet the wants of those who ask about "Tesla" coils. "Early coils" and "later coils" vary in configuration and setup. Tesla coils in general are very popular devices among high-voltage enthusiasts.

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Selected biography

Aristarchus of Samos
Aristarchus (310 BC - c. 230 BC) was a Greek astronomer and mathematician, born on the island of Samos, in ancient Greece. He was the first Greek astronomer to propose a heliocentric model of the solar system, placing the Sun, not the Earth, at the center of the known universe (hence he is sometimes known as the "Greek Copernicus"). His astronomical ideas were not well-received and were displaced by those of Aristotle and Ptolemy, until they were successfully revived and developed by Copernicus nearly 2000 years later. The Aristarchus crater on the Moon was named in his honor.

Aristarchus believed the stars to be very far away, and saw this as the reason why there was no visible parallax, that is, an observed movement of the stars relative to each other as the Earth moved around the Sun.

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Did you know...

by Jon Lomberg

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Science News

Science news on Wikipedia
  • February 11: A rat study found that rats given artificial sweetener gained more weight than those on a sugar diet. Scientists speculate the body increases the metabolism anticipating calories that never come, then requires more food to make up the shortfall. (SciAm)
  • February 8: The first commercial vessel to use a kite to help save fuel created by SkySails finished its maiden voyage. Estimates are that the ship saved 10-15% fuel while the kite was in use, which translates into $1,000 to $1,500 in fuel costs per day.(Nature)
  • February 7: A new knee device is demonstrated that can generate electricity efficiently from walking with minimal effort. The system acquires energy from deceleration similar to how hybrid-electric cars regain energy from regenerative braking. (CBC)
Science news on Wikinews
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