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Nuclear Energy Science Tracer Bullet (Library of Congress)
Nuclear Power (Wolfram Alpha)
These are organized by a classification scheme developed exclusively for Cosma. More…
CODATA Internationally recommended values of the Fundamental Physical Constants, Atomic and Nuclear (NIST Reference on Constants, Units and Uncertainty)
Radiation, Radioactivity & Radiobiology (Martindale’s Reference Desk)
atom : the smallest particle of an element that can exist either alone or in combination — Webster
Atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small; typical sizes are around 100 picometers (a ten-billionth of a meter, in the short scale).
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and typically a similar number of neutrons. Protons and neutrons are called nucleons. More than 99.94% of an atom’s mass is in the nucleus. The protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge. If the number of protons and electrons are equal, that atom is electrically neutral. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion.
The electrons of an atom are attracted to the protons in an atomic nucleus by this electromagnetic force. The protons and neutrons in the nucleus are attracted to each other by a different force, the nuclear force, which is usually stronger than the electromagnetic force repelling the positively charged protons from one another. Under certain circumstances, the repelling electromagnetic force becomes stronger than the nuclear force, and nucleons can be ejected from the nucleus, leaving behind a different element: nuclear decay resulting in nuclear transmutation.
The number of protons in the nucleus defines to what chemical element the atom belongs: for example, all copper atoms contain 29 protons. The number of neutrons defines the isotope of the element. The number of electrons influences the magnetic properties of an atom. Atoms can attach to one or more other atoms by chemical bonds to form chemical compounds such as molecules. The ability of atoms to associate and dissociate is responsible for most of the physical changes observed in nature and is the subject of the discipline of chemistry. — Wikipedia
Atomic Physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. It is primarily concerned with the arrangement of electrons around the nucleus and the processes by which these arrangements change.
The term atomic physics can be associated with nuclear power and nuclear weapons, due to the synonymous use of atomic and nuclear in standard English. Physicists distinguish between atomic physics — which deals with the atom as a system consisting of a nucleus and electrons — and nuclear physics, which considers atomic nuclei alone. — Wikipedia
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions. Other forms of nuclear matter are also studied. Nuclear physics should not be confused with atomic physics, which studies the atom as a whole, including its electrons. — Wikipedia
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
North Korea's 2017 bomb test set off later...
on September 24, 2018 at 10:47 pm
Using newly refined analysis methods, scientists have discovered that a North Korean nuclear bomb test last fall set off aftershocks over a period of eight months. The shocks, which occurred on a previously unmapped nearby fault, are a window into both the physics of nuclear explosions, and how natural earthquakes can be triggered. The findings are described in two papers just published online in the journal Seismological Research Letters. […]
New observations to understand the phase...
on September 21, 2018 at 10:52 am
The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved nearly freely in a quark-gluon plasma. Then, in a phase […]
Physicists develop a more accurate solution for...
on September 19, 2018 at 11:14 am
Researchers at the RUDN University have developed a mathematical method to solve the quantum Coulomb three-body problem for bound states with high accuracy. They also showed that previous calculations performed by a group of Japanese scientists are incorrect. The work will contribute to more accurate calculations of the trajectories of quantum particles in space, and its results will be useful in solving fundamental problems of physics. The paper was published in the journal Physical Review A. […]
Why nuclear energy should be part of Africa's...
on September 17, 2018 at 1:40 pm
Africa has the least nuclear power of any continent in the world, with the exception of Australia where nuclear power is banned. All the largest economies in the world have nuclear power as part of their energy mix. […]
World speed record for polymer simulations...
on September 17, 2018 at 11:49 am
From a humble plastic bag to ultra-light airplane wings, polymers are everywhere. These molecules are long chains of atoms that play many roles for good and bad, from organic photovoltaics to indestructible plastic pollution. Polymers are useful in liquid form, as well: The difference between tomato puree and ketchup is merely 0.5 percent of xanthan gum, which is a polymer made from sugar. Ketchup is thick but not sticky, thanks to xanthan chains that are so long that they interpenetrate and […]