Rock is a form of popular music that emerged in the 1950s and that by the end of the 20th century was the world’s dominant form of popular music. It originated in the United States and spread …

Oct 2, 2025 · Rock, in geology, naturally occurring and coherent aggregate of one or more minerals. Such aggregates constitute the basic unit of which the solid Earth is composed and …

First, that rock is so broad a musical category that in practice people organize their tastes around more focused genre labels: the young Presley was a rockabilly, the Beatles a pop group, …

Sep 28, 2025 · Rock Hudson, American actor noted for his good looks and movie roles during the 1950s and ’60s, including Magnificent Obsession, Giant, and Pillow Talk, and for the TV series …

In Britain, as in the rest of Europe, rock and roll had an immediate youth appeal—each country soon had its own Elvis Presley—but it made little impact on national music media, as …

Rock - 80s, 90s, Pop: The music industry was rescued from its economic crisis by the development in the 1980s of a new technology, digital recording. Vinyl records were replaced …

Oct 2, 2025 · Rock - Electrical Properties: The electrical nature of a material is characterized by its conductivity (or, inversely, its resistivity) and its dielectric constant, and coefficients that …

Rock remains the most democratic of mass media—the only one in which voices from the margins of society can still be heard out loud. Yet, at the beginning of the 21st century, rock and the …

Oct 8, 2025 · Lava, magma (molten rock) emerging as a liquid onto Earth’s surface. The term ‘lava’ is also used for the solidified rock formed by the cooling of a molten lava flow.

Oct 18, 2025 · Metamorphism can occur either when a rock moves from one position to another along a single geotherm or when the geotherm itself changes form. The former can take place …