Columbia Encyclopedia

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barcode

(Encyclopedia)CE5 Barcode barcode, computer coding system that uses a printed pattern of lines and bars to identify such things as products, mail and packages, and customer accounts; the term also is used for s...

genetics

(Encyclopedia)genetics, scientific study of the mechanism of heredity. While Gregor Mendel first presented his findings on the statistical laws governing the transmission of certain traits from generation to genera...

harmonic motion

(Encyclopedia)CE5 Harmonic motion is exhibited by a weight vibrating on the end of a spring. In A, the displacement of the object from its equilibrium position and the acceleration of the object are at a maximum...

activation energy

(Encyclopedia)CE5 Energy profile of an exothermic reaction: Although the total energy of the products is less than that of the reactants, the activation energy must be added to weaken or break existing bonds bef...

smart card

(Encyclopedia)smart card, small device that resembles a credit card but contains an embedded microprocessor to store and process information. Magnetic-stripe cards, which store a very small amount of information (m...

sickle cell disease

(Encyclopedia)sickle cell disease or sickle cell anemia, inherited disorder of the blood in which the oxygen-carrying hemoglobin pigment in erythrocytes (red blood cells) is abnormal. This “hemoglobin-S” crysta...

particle accelerator

(Encyclopedia)CE5 Linear accelerator (LINAC) CE5 Cyclotron: As the charged particles move faster, they spiral out to the edge of the Ds. particle accelerator, apparatus used in nuclear physics to produce bea...

stove

(Encyclopedia)stove, device used for heating or for cooking food. The stove was long regarded as a cooking device supplementary to the fireplace, near which it stood; its stovepipe led into the fireplace chimney. I...

television

(Encyclopedia)CE5 Video transmission and reception of color and black-and-white television: The camera lens focuses collected light rays into mirrors, which separate the image into its three primary color compon...

helium

(Encyclopedia)helium hēˈlēəm [key], gaseous chemical element; symbol He; at. no. 2; at. wt. 4.0026; m.p. below −272℃ at 26 atmospheres pressure; b.p. −268.934℃ at 1 atmosphere pressure; density 0.1785 g...