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cosmic rays

(Encyclopedia)cosmic rays, charged particles moving at nearly the speed of light reaching the earth from outer space. Primary cosmic rays consist mostly of protons (nuclei of hydrogen atoms), some alpha particles (...

electricity

(Encyclopedia)CE5 Electrical and radio symbols electricity, class of phenomena arising from the existence of charge. The basic unit of charge is that on the proton or electron—the proton's charge is designate...

aerogel

(Encyclopedia)aerogel, any of a group of extremely light and porous solid materials; the lightest is less than four times as dense as dry air. Aerogels are produced from certain gels (see colloid) by heating the ge...

Tomonaga, Sinichiro

(Encyclopedia)Tomonaga, Sinichiro or Sin-Itiro, 1906–79, Japanese physicist, Ph.D. Kyoto Imperial Univ., 1939. He was a professor at Bunrika Univ. (now Tokyo Univ. of Education) from 1941 to 1956, then served pre...

quantum chromodynamics

(Encyclopedia)quantum chromodynamics (QCD), quantum field theory that describes the properties of the strong interactions between quarks and between protons and neutrons in the framework of quantum theory. Quarks p...

charge

(Encyclopedia)charge, property of matter that gives rise to all electrical phenomena (see electricity). The basic unit of charge, usually denoted by e, is that on the proton or the electron; that on the proton is d...

strong interactions

(Encyclopedia)strong interactions, actions between elementary particles mediated, or carried, by gluons. They are responsible for the binding of protons and neutrons in the nucleus and interactions between quarks. ...

spark chamber

(Encyclopedia)spark chamber, in physics, device for recording the passage of elementary particles produced by reactions in a particle accelerator. Particles pass through a stack of metal plates or wire grids that a...

force

(Encyclopedia)force, commonly, a “push” or “pull,” more properly defined in physics as a quantity that changes the motion, size, or shape of a body. Force is a vector quantity, having both magnitude and dir...

kindergarten

(Encyclopedia)kindergarten [Ger.,=garden of children], system of preschool education. Friedrich Froebel designed (1837) the kindergarten to provide an educational situation less formal than that of the elementary s...