The piano (an abbreviation of pianoforte) is a musical instrument played using a keyboard. It is widely employed in classical and jazz music for solo and ensemble performances, accompaniment, and for composing and rehearsal. Although the piano is not portable and often expensive, its versatility and ubiquity have made it one of the world's most familiar musical instruments. Inheriting the folk tradition of the protest song, rock music has been associated with political activism as well as changes in social attitudes to race, sex and drug use, and is often seen as an expression of youth revolt against adult consumerism and conformity. The terms "popular music" and "pop music" are often used interchangeably, although the former is a description of music which is popular (and can include any style). Rock music also drew strongly on a number of other genres such as electric blues and folk, and incorporated influences from jazz, classical and other musical sources. By the late 1960s, referred to as the "golden age" or "classic rock" period, a number of distinct rock music subgenres had emerged, including hybrids like blues rock, folk rock, country rock, raga rock, and jazz-rock fusion, many of which contributed to the development of psychedelic rock, which was influenced by the countercultural psychedelic scene. records for singles "revolutionized the manner in which pop has been disseminated" and helped to move pop music to 'a record/radio/film star system'. Another technological change was the widespread availability of television in the 1950s; with televised performances, "pop stars had to have a visual presence". In the 1960s, the introduction of inexpensive, portable transistor radios meant that teenagers could listen to music outside of the home. Multi-track recording (from the 1960s); and digital sampling (from the 1980s) have also been utilized as methods for the creation and elaboration of pop music. By the early 1980s, the promotion of pop music had been greatly affected by the rise of Music Television channels like MTV, which "favoured those artists such as Michael Jackson and Madonna who had a strong visual appeal". since the late 1950s, however, pop has had the special meaning of non-classical mus[ic], usually in the form of songs, performed by such artists as the Beatles, the Rolling Stones, ABBA, etc". Grove Music Online also states that "...
The piano was founded on earlier technological innovations. in the early 1960s [the term] 'pop music' competed terminologically with Beat music [in England], while in the USA its coverage overlapped (as it still does) with that of 'rock and roll'". The sound of rock is traditionally centered on the electric guitar, which emerged in its modern form in the 1950s with the popularization of rock and roll, and was influenced by the sounds of electric blues guitarists. The sound of an electric guitar in rock music is typically supported by an electric bass guitar pioneered in jazz music in the same era, and percussion produced from a drum kit that combines drums and cymbals. This trio of instruments has often been complemented by the inclusion of others, particularly keyboards such as the piano, Hammond organ and synthesizers. The basic rock instrumentation was adapted from the basic blues band instrumentation (prominent lead guitar, second chord instrument, bass, and drums). A group of musicians performing rock music is termed a rock band or rock group and typically consists of between two and five members. Classically, a rock band takes the form of a quartet whose members cover one or more roles, including vocalist, lead guitarist, rhythm guitarist, bass guitarist, drummer and often that of keyboard player or other instrumentalist. Pop music (a term that originally derives from an abbreviation of "popular") is a genre of popular music, which originated in its modern form in the Western world during the 1950s and 1960s, deriving from rock and roll. Rock music has also embodied and served as the vehicle for cultural and social movements, leading to major sub-cultures including mods and rockers in the UK and the hippie counterculture that spread out from San Francisco in the US in the 1960s.
The invention of the modern piano is credited to Bartolomeo Cristofori (1655-1731) of Padua, Italy, who was employed by Ferdinando de' Medici, Grand Prince of Tuscany, as the Keeper of the Instruments; he was an expert harpsichord maker, and was well acquainted with the body of knowledge on stringed keyboard instruments. It is not known exactly when Cristofori first built a piano. An inventory made by his employers, the Medici family, indicates the existence of a piano by the year 1700; another document of doubtful authenticity indicates a date of 1698. The three Cristofori pianos that survive today date from the 1720s.
Some early pianos had shapes and designs that are no longer in use. The square piano (not truly square, but rectangular) was cross strung at an extremely acute angle above the hammers, with the keyboard set along the long side. Typically, rock is song-based music usually with a 4/4 time signature using a verse-chorus form, but the genre has become extremely diverse. New genres that emerged from this scene included progressive rock, which extended the artistic elements; glam rock, which highlighted showmanship and visual style; and the diverse and enduring subgenre of heavy metal, which emphasized volume, power, and speed. It is "not driven by any significant ambition except profit and commercial reward ... It has also made use of technological innovation.