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capacitor

(Encyclopedia)capacitor or condenser, device for the storage of electric charge. Simple capacitors consist of two plates made of an electrically conducting material (e.g., a metal) and separated by a nonconducting ...

Richter, Gerhard

(Encyclopedia)Richter, Gerhard gārˈhärt rĭkhˈtər [key], 1932–, German painter, b. Dresden, studied Academy of Fine Arts, Dresden (1951–56) and Düsseldorf (1961–63). Widely considered one of the foremos...

pen

(Encyclopedia)pen, pointed implement used in writing or drawing to apply ink or a similar colored fluid to any surface, such as paper. Various kinds of pens have been used since ancient times. Reeds that were slit ...

platinum

(Encyclopedia)platinum plătˈənəm [key], metallic chemical element; symbol Pt; at. no. 78; at. wt. 195.084; m.p. 1,772℃; b.p. 3,827±100℃; sp. gr. 21.45 at 20℃; valence +2 or +4. Pure platinum is a malleab...

potassium

(Encyclopedia)potassium pətăsˈēəm [key], a metallic chemical element; symbol K [Lat. kalium=alkali]; at. no. 19; at. wt. 39.0983; m.p. 63.25℃; b.p. 760℃; sp. gr. .862 at 20℃; valence +1. Potassium is a s...

diffraction

(Encyclopedia)diffraction, bending of waves around the edge of an obstacle. When light strikes an opaque body, for instance, a shadow forms on the side of the body that is shielded from the light source. Ordinarily...

feldspar

(Encyclopedia)feldspar fĕlˈspär [key], an abundant group of rock-forming minerals which constitute 60% of the earth's crust. Chemically the feldspars are silicates of aluminum, containing sodium, potassium, iron...

Hirst, Damien Steven

(Encyclopedia)Hirst, Damien Steven, 1965–, British artist-provacateur, b. Bristol. While at Goldsmiths College, London (grad. 1988), he organized the exhibition Freeze, whose participants, led by Hirst, became kn...

Geiger counter

(Encyclopedia)Geiger counter or Geiger-Müller (G-M) counter gīˈgər-mŭlˈər, –myo͞oˈlər [key], instrument for the detection and quantitative determination of ionizing radiation such as the alpha and beta ...

Galveston

(Encyclopedia)Galveston gălˈvəstən [key], city (2020 pop. 50,546), seat of Galveston co., on Galveston ...