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Shackleton, Sir Ernest Henry

(Encyclopedia)Shackleton, Sir Ernest Henry, 1874–1922, British antarctic explorer, b. Ireland. The first of his voyages to Antarctica was made as a member of the expedition (1901–4) of Robert F. Scott. Shacklet...

gadolinium

(Encyclopedia)gadolinium gădəlĭnˈēəm [key], metallic chemical element; symbol Gd; at. no. 64; at. wt. 157.25; m.p. 1,312℃; b.p. 3,233℃; sp. gr. 7.898 at 25℃; valence +3. Gadolinium is a malleable, ducti...

amplifier

(Encyclopedia)amplifier, device that accepts a varying input signal and produces an output signal that varies in the same way as the input but has a larger amplitude. The input signal may be a current, a voltage, a...

chromosphere

(Encyclopedia)chromosphere krōˈməsfērˌ [key] [Gr.,=color sphere], layer of rarefied, transparent gases in the solar atmosphere; it measures 6,000 mi (9,700 km) in thickness and lies between the photosphere (th...

Akbar

(Encyclopedia)Akbar ăkˈbär [key], 1542–1605, Mughal emperor of India (1556–1605); son of Humayun, grandson of Babur. He succeeded to the throne under a regent, Bairam Khan, who rendered loyal service in expa...

gyroscope

(Encyclopedia)CE5 Three-frame gyroscope gyroscope jīˈrəskōpˌ [key], symmetrical mass, usually a wheel, mounted so that it can spin about an axis in any direction. When spinning, the gyroscope has special p...

Joplin, Scott

(Encyclopedia)Joplin, Scott jŏpˈlĭn [key], 1868–1917, American ragtime pianist and composer, b. Texarkana, Tex. Self-taught, Joplin left home in his early teens to seek his fortune in music. He lived in St. Lo...

neutron

(Encyclopedia)neutron, uncharged elementary particle of slightly greater mass than the proton. It was discovered by James Chadwick in 1932. The stable isotopes of all elements except hydrogen and helium contain a n...

proton

(Encyclopedia)proton, elementary particle having a single positive electrical charge and constituting the nucleus of the ordinary hydrogen atom. The positive charge of the nucleus of any atom is due to its protons....

pump

(Encyclopedia)pump, device to lift, transfer, or increase the pressure of a fluid (gas or liquid) or to create a vacuum in an enclosed space by the removal of a gas (see vacuum pumps under vacuum). The centrifugal ...