Radioactivity was first reported in 1896 by the French physicist Henri Becquerel for a double salt of uranium and potassium. Soon thereafter it was found that all uranium compounds and the metal itself were similarly radioactive.
Radioactivity
(a) Emission of particles by unstable elements as they decay.
(b) The spontaneous disintegration of unstable atomic nuclei. All natural radioactive elements heavier than lead are daughter products of either 232Th (half-life 1.
Radioactivity- the spontaneous breakdown of one type of atomic nucleus into another
Red giant- an old star whose outer layers have billowed out and cooled down ...
Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.
Radioactivity: The spontaneous breaking apart, or decay, of unstable nuclei in isotopes. The unstable radioactive isotope is called the parent, and the products of the decay of the parent are called the daughter isotopes.
Radioactivity - The spontaneous disintegration of an unstable nucleus of an atom ...
[edit] Radioactivity and nuclear energy
It was quickly noted after the discovery of radioactivity in 1897, that the total energy due to radioactive processes is about one million times greater than that involved in any known molecular change.
INDUCED RADIOACTIVITY - Radioactivity produced in materials, especially metals, exposed to high-energy photons or neutrons.
INERT GASES - Noble gases.
Radioactivity
The spontaneous decay of certain rare, unstable, atomic nuclei into more stable atomic nuclei. A natural by-product of this process is the release of energy.
Rate Sensor Units (RSUs) ...
radioactivity The release of energy by rare, heavy elements when their nuclei decay into lighter nuclei.
radioactivity - (n.)
Spontaneous emission of alpha, beta, or gamma rays by the disintegration of the nuclei of atoms.
radio galaxy - (n.) ...
(a) Unit of radioactivity. 1 curie = 3.7 × 1010 disintegrations per second. [H76]
(b) A unit of radioactivity which is now defined as the quantity of any radioactive nuclide undergoing 37.00 × 109 disintegrations per second.
The inner core is believed to be solid and the outer core is liquid. The major heat source of the core is the natural radioactivity in the Earth. Outside the core is the mantle, which is partially melted.
= radioactivity. radiation belt An envelope of charged particles trapped in the magnetic field of a spatial body. See Van Allen belt. radiation constants Values used in Planck law and other radiation calculations.
Geiger counter (NASA SP-7, 1965) An instrument for detecting and measuring radioactivity. In full, Geiger-Muller counter.
After the discovery of radioactivity by Henri Becquerel in 1896, it was generally believed that atmospheric electricity (ionization of the air) was caused only by radiation from radioactive elements in the ground or the radioactive gases (isotopes of ...
Natural radioactivity, lightning, volcanism, solar ultraviolet radiation, and meteoritic impacts all provided large amounts of energy that eventually shaped the ammonia, methane, carbon dioxide, ...
Radioactivity. The process of emitting particles from the nucleus. Usage: 'Certain materials found in nature demonstrate radioactivity.' Misuse alert: Radioactivity is a process, not a thing, and not a substance.
In fact, the total amount of radioactivity released by man is inconsequential to the large quantities of radioactivity in the natural environment [2] (pdf).
Artificial radiation sources ...
radiation emitted in one of the three types of natural radioactivity. It is the most energetic form of electromagnetic radiation, with a very short wavelength of less than 10−10 m.
But continued contraction of these materials caused them to heat, as did the radioactivity of some of the heavier elements. In the next stage of its formation, as the earth became hotter, it began melting under the influence of gravity.
The first was the discovery of radioactivity by the French physicist Anton Henri Becquerel (1852:1908), who found that some materials emitted a mysterious radiation that would fog photographic film.
It's not quite correct to call this "radioactivity", which is different from radiation. Radiation can refer to a lot of things: sunlight, broadcast signal from a station, in your microwave oven, ... Some are dangerous, some are not.
She was a pioneer in the field of radioactivity, the first person honored with two Nobel Prizes, and the first female professor at the University of Paris....
and her two daughters, but Maric was delayed temporarily due to Eduard's illness.
Most of the heat inside the much smaller Earth and Venus is produced from radioactivity in the rocky material (in fact, the higher radioactive heating long ago may have been necessary for the terrestial planets to undergo differentiation).
In the proton-proton cycle, two hydrogen nuclei (protons) are fused and one of these protons is converted to a neutron by beta decay (see radioactivity) to make a deuterium nucleus (one proton and one neutron).
When referring to radioactivity, radiation is the emission of either waves (electromagnetic radiation) or particles (particle radiation). Light can fall into either of these categories, as it is both a wave and particle.
Our laboratory work shows that the process of radioactivity is not affected by temperature, pressure, or other outside factors, and proceeds at a rate set only by the little natural clocks built into the nucleus of the atom.
Meteorites can be either rock, metal (nickel and iron) or a mixture of both. Stony meteorites are difficult to identify. They do not glow or give off radioactivity. Stones outnumber metals.
The Moon has much less mass in it compared to the Earth, so there was much less radioactivity and therefore much less heat. The Moon is a much smaller object with a much thinner mantle, so it doesn't take very long for the heat to escape into space.
Different isotopes of a given element have different numbers of neutrons in the nucleus. The total number of neutrons and protons affects properties such as radioactivity or stability, the types of nuclear reactions, if any, ...
 See also: Energy, Earth, Light, Time, Element
  
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