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. Harmonies range from the common triad to parallel fourths and fifths and dissonant harmonic progressions. Rock songs, since the late 1950s and particularly from the mid-1960s onwards, often used the verse-chorus structure derived from blues and folk music, but there has been considerable variation from this model. Critics have stressed the eclecticism and stylistic diversity of rock. Because of its complex history and tendency to borrow from other musical and cultural forms, it has been argued that "it is impossible to bind rock music to a rigidly delineated musical definition. As a genre, pop music is extremely eclectic, often borrowing elements from other styles including urban, dance, rock, Latin and country; nonetheless, there are core elements which define pop. Rock music is traditionally built on a foundation of simple unsyncopated rhythms in a 4/4 meter, with a repetitive snare drum back beat on beats two and four. Melodies are often derived from older musical modes, including the Dorian and Mixolydian, as well as major and minor modes. Rock places a higher degree of emphasis on musicianship, live performance, and an ideology of authenticity than pop music. 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. Unlike many earlier styles of popular music, rock lyrics have dealt with a wide range of themes in addition to romantic love: including sex, rebellion against "The Establishment", social concerns and life styles. These themes were inherited from a variety of sources, including the Tin Pan Alley pop tradition, folk music and rhythm and blues. Music journalist Robert Christgau characterizes rock lyrics as a "cool medium" with simple diction and repeated refrains, and asserts that rock's primary "function" "pertains to music, or, more generally, noise." The predominance of white, male and often middle class musicians in rock music has often been noted and rock has been seen as an appropriation of black musical forms for a young, white and largely male audience. As a result, it has been seen as articulating the concerns of this group in both style and lyrics.
The piano was founded on earlier technological innovations. It has also made use of technological innovation. 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. 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 "... Similarly, 1970s punk culture spawned the visually distinctive goth and emo subcultures. 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.
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. 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. Since the term rock began to be used in preference to rock and roll from the late-1960s, it has often been contrasted with pop music, with which it has shared many characteristics, but from which it is often distanced by an emphasis on musicianship, live performance and a focus on serious and progressive themes as part of an ideology of authenticity that is frequently combined with an awareness of the genre's history and development. According to Simon Frith "rock was something more than pop, something more than rock and roll. Pop music has been dominated by the American and (from the mid-1960s) British music industries, whose influence has made pop music something of an international monoculture, but most regions and countries have their own form of pop music, sometimes producing local versions of wider trends, and lending them local characteristics. Some of these trends (for example Europop) have had a significant impact of the development of the genre. Rock musicians combined an emphasis on skill and technique with the romantic concept of art as artistic expression, original and sincere". In the new millennium the term rock has sometimes been used as a blanket term including forms such as pop music, reggae music, soul music, and even hip hop, with which it has been influenced but often contrasted through much of its history..