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physics

(Encyclopedia)physics, branch of science traditionally defined as the study of matter, energy, and the relation between them; it was called natural philosophy until the late 19th cent. and is still known by this na...

chemistry

(Encyclopedia)chemistry, branch of science concerned with the properties, composition, and structure of substances and the changes they undergo when they combine or react under specified conditions. Organic chemi...

dating

(Encyclopedia)dating, the determination of the age of an object, of a natural phenomenon, or of a series of events. There are two basic types of dating methods, relative and absolute. In relative dating, the tempor...

nucleus, in physics

(Encyclopedia)nucleus, in physics, the extremely dense central core of an atom. Following the discovery of radioactivity by A. H. Becquerel in 1896, Ernest Rutherford identified two types of radiation given off b...

element

(Encyclopedia)CE5 element, in chemistry, a substance that cannot be decomposed into simpler substances by chemical means. A substance such as a compound can be decomposed into its constituent elements by means o...

elementary particles

(Encyclopedia)CE5 elementary particles, the most basic physical constituents of the universe. The first subatomic particle to be discovered was the electron, identified in 1897 by J. J. Thomson. After the...

science

(Encyclopedia)science [Lat. scientia=knowledge]. For many the term science refers to the organized body of knowledge concerning the physical world, both animate and inanimate, but a proper definition would also hav...