Columbia Encyclopedia

Search results

325 results found

flame

(Encyclopedia)flame, phenomenon associated with the chemical reaction of a gas that has been heated above its kindling temperature with some other gas, usually atmospheric oxygen (see combustion). The heat and ligh...

cold fusion

(Encyclopedia)cold fusion or low-temperature fusion, nuclear fusion of deuterium, an isotope of hydrogen, at or relatively near room temperature. Fusion, the reaction involved in the release of the destructive ener...

coal gas

(Encyclopedia)coal gas, gas obtained in the destructive distillation of soft coal, as a byproduct in the preparation of coke. Its composition varies, but in general it is made up largely of hydrogen and methane wit...

cream of tartar

(Encyclopedia)cream of tartar, white crystalline powder. Chemically it is potassium hydrogen tartrate, KC4H5O6, the acidic potassium salt of tartaric acid. It is used as the leavening agent in baking powders. An im...

interstellar matter

(Encyclopedia)interstellar matter, matter in a galaxy between the stars, known also as the interstellar medium. The interstellar gas, which constitutes about 99% of the interstellar matter, consists mostly of hyd...

photosynthesis

(Encyclopedia)photosynthesis fōˌtōsĭnˈthəsĭs [key], process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the pr...

oxidation and reduction

(Encyclopedia)oxidation and reduction, complementary chemical reactions characterized by the loss or gain, respectively, of one or more electrons by an atom or molecule. Originally the term oxidation was used to re...

iodoform

(Encyclopedia)iodoform īōˈdəfôrmˌ [key], CHI3, yellow crystalline solid that has a penetrating odor. It melts at 119℃ and is insoluble in water but soluble in ether or ethanol. Iodoform was formerly used as...

methyl

(Encyclopedia)methyl mĕthˈəl [key], CH3, organic free radical or alkyl group derived from methane by the removal of one hydrogen atom. ...

Ångström, Anders Jöns

(Encyclopedia)Ångström, Anders Jöns änˈdərs yöns ōngˈström [key], 1814–74, Swedish physicist. He was educated at the Univ. of Uppsala and in 1839 became a member of its faculty. He is particularly noted...