Columbia Encyclopedia

Search results

26 results found

Huggins, Sir William

(Encyclopedia)Huggins, Sir William, 1824–1910, English astronomer. Using a spectroscope, he began to study the chemical constitution of stars from the observatory attached to his home in Tulse Hill, London. He pr...

photocopying

(Encyclopedia)photocopying, process whereby written or printed matter is directly copied by photographic techniques. Generally, photocopying is practical when just a few copies of an original are needed. When many ...

ice cream

(Encyclopedia)ice cream, sweet frozen dessert, made from milk fat and solids, sugar, flavoring, a stabilizer (usually gelatin), and sometimes eggs, fruits, or nuts. The mix is churned at freezing temperature to att...

alum

(Encyclopedia)alum ălˈəm [key], any one of a series of isomorphous double salts that are hydrated sulfates of a univalent cation (e.g., potassium, sodium, ammonium, cesium, or thallium) and a trivalent cation (e...

glycine

(Encyclopedia)CE5 glycine glīˈsēn [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Glycine is the only one of these amino acids that is not optically active, i.e., it does...

food additives

(Encyclopedia)food additives, substances added to foods by manufacturers to prevent spoilage or to enhance appearance, taste, texture, or nutritive value. By quantity, the most common food additives are flavorings,...

adhesive

(Encyclopedia)adhesive, substance capable of sticking to surfaces of other substances and bonding them to one another. The term adhesive cement is sometimes used in place of adhesive, especially when referring to a...

lithography

(Encyclopedia)lithography lĭthŏgˈrəfē [key], type of planographic or surface printing. It is distinguished from letterpress (relief) printing and from intaglio printing (in which the design is cut or etched in...

Nobel, Alfred Bernhard

(Encyclopedia)Nobel, Alfred Bernhard älˈfrĕd bĕrnˈhärd nōbĕlˈ [key], 1833–96, Swedish chemist and inventor. Educated in St. Petersburg, Russia, he traveled as a youth and returned to St. Petersburg in 18...

seaweed

(Encyclopedia)seaweed, name commonly used for the multicellular marine algae. Simpler forms, consisting of one cell (e.g., the diatom) or of a few cells, are not generally called seaweeds; these tiny plants help to...

Browse by Subject