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colloid

(Encyclopedia)colloid kŏlˈoid [key] [Gr.,=gluelike], a mixture in which one substance is divided into minute particles (called colloidal particles) and dispersed throughout a second substance. The mixture is also...

formula, in chemistry

(Encyclopedia)formula, in chemistry, an expression showing the chemical composition of a compound. Formulas of compounds are used in writing the equations (see chemical equations) that represent chemical reactions....

acids and bases

(Encyclopedia)acids and bases, two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water. Another theory that provides a very broad ...

laser

(Encyclopedia)CE5 Ordinary light sources produce incoherent light, while a laser produces a beam of coherent light. laser [acronym for light amplification by stimulated emission of radiation], device for the cr...

water

(Encyclopedia)CE5 A. Water molecule (black circles represent valence-shell electrons) B. Structure of ice: Each oxygen atom (white circles) is bonded to four other oxygen atoms by hydrogen bonds, the hydrogen at...

coenzyme

(Encyclopedia)coenzyme kō-ĕnˈzīm [key], any one of a group of relatively small organic molecules required for the catalytic function of certain enzymes. A coenzyme may either be attached by covalent bonds to a ...

quantum theory

(Encyclopedia)quantum theory, modern physical theory concerned with the emission and absorption of energy by matter and with the motion of material particles; the quantum theory and the theory of relativity togethe...

virus

(Encyclopedia)CE5 Structure of a tobacco mosaic virus, an RNA-containing virus virus, parasite with a noncellular structure composed mainly of nucleic acid within a protein coat. Most viruses are too small (100...

rocket, in aeronautics

(Encyclopedia)CE5 Relative positions of the components of the Saturn V rocket, the U.S. space vehicle used in the moon missions rocket, any vehicle propelled by ejection of the gases produced by combustion of s...

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...