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Gram's stain

(Encyclopedia)Gram's stain, laboratory staining technique that distinguishes between two groups of bacteria by the identification of differences in the structure of their cell walls. The Gram stain, named after its...

firefly

(Encyclopedia)firefly or lightning bug, small, luminescent, carnivorous beetle of the family Lampyridae. Fireflies are well represented in temperate regions, although the majority of species are tropical and subtro...

3D printer

(Encyclopedia)3D printer, computerized device that produces a three-dimensional object by creating it as a series of thin layers. The object is created from a model stored in computer-aided design file; the model i...

oils

(Encyclopedia)oils, term commonly used to indicate a variety of greasy, fluid substances that are, in general, viscous liquids at ordinary temperatures, less dense than water, insoluble in water but soluble in alco...

embryo

(Encyclopedia)CE5 Development of the human embryo embryo ĕmˈbrēō [key], name for the developing young of an animal or plant. In its widest definition, the embryo is the young from the moment of fertilizatio...

hydrogen bomb

(Encyclopedia)hydrogen bomb or H-bomb, weapon deriving a large portion of its energy from the nuclear fusion of hydrogen isotopes. In an atomic bomb, uranium or plutonium is split into lighter elements that togethe...

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...

penguin

(Encyclopedia)penguin, originally the common name for the now extinct great auk of the N Atlantic and now used (since the 19th cent.) for the unrelated, generally antarctic diving birds of the Southern Hemisphere. ...

adrenal gland

(Encyclopedia)CE5 Adrenal glands: The cross-sectioned area shows the adrenal cortex and medulla. adrenal gland so͞oprərēnˈəl [key], endocrine gland (see endocrine system) about 2 in. (5.1 cm) long situated...

chromatography

(Encyclopedia)chromatography krōˌmətŏgˈrəfē [key], resolution of a chemical mixture into its component compounds by passing it through a system that retards each compound to a varying degree; a system capabl...