Popular or pop music is largely vocal and appeals to a large, mainly young audience. It was originally available as single or long-playing (LP) vinyl records, but is now almost entirely sold on compact discs (CDs). Its popularity is measured by THE CHARTS.
Popular music began in the US in the 1930s with a lively new music called swing. Bing Crosby and Frank Sinatra sang with big swing bands and later became solo stars. During the 1950s, rock and roll—a louder and more exciting type of pop music—emerged with songs about youthful rebellion and teenage love.
The main form of popular music is pop itself. Pop bands usually have singers, guitarists, keyboard players, and percussists. Rock music has a heavier sound and is guitar-led. Reggae from Jamaica, country from the US, and national folk music, such as rai from Algeria, are also popular around the world.
The charts measure the popularity of a record by the number of copies it has sold in a given period, usually a week. Most pop musicians dream of reaching number one. Charts show top sellers, highest new entries, fastest climbers, and records on the way down.
Music magazines, radio and television companies, and other organizations all compile their own charts. The best-known charts are the weekly charts for albums and singles, but there are also charts for different types of music, such as classical or jazz. Charts cover different regions, such as a country, and different periods, such as a month or a year.
A record gets to number one because it has sold more copies than any other record over a specified time. In case a record company or performer tries to influence the charts by artificially boosting sales (with reduced prices or other tricks), all charts are independently checked to ensure their accuracy.