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 to other …

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 music …

Rock, or stone, is a hard material made up of one or more minerals. Rock makes up the outer layer of Earth, called the crust. The lower parts of this layer are solid rock, or…

Nov 25, 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 typically form …

The Beatles’ success suggested that it was possible to enjoy the commercial, mass-cultural power of rock and roll while remaining an artist. The immediate consequence was folk rock. Folk musicians, …

Rock music is a form of popular music that emerged in the 1950s and can be defined as “a form of music with a strong beat”—it is difficult to be much more precise. It is also called rock and roll.

Fifty years after rock’s birth as an alternative to mainstream pop, mainstream pop had become rock. Whatever now happens to the music industry, it is certain that rock will remain the soundscape for …

Introduction Sedimentary rock is one of three types of rock found on Earth. The others are called igneous and metamorphic. Igneous and metamorphic rocks are the most common rock types in …

Limestone is a sedimentary rock that can be metamorphosed, or changed, to make marble. Limestone and marble are both formed from a chemical called calcium carbonate.

Introduction Rock is a naturally occurring solid material composed of one or more minerals. It is a basic component of Earth, providing the main substance of all but the innermost layers. The outer layer of …