Most music is made of tones (symbolized by musical notes) with definite pitcheses. Different tones, played one after the other constitute a melody, when they are heard as some sort of unit. While a unit of different tones played simultaneously make chordss, and the succession of chords in time makes a "progression". The study of progressions of chords is called harmony. Sounds of indefinite pitch sounds are often provided by percussion. The temporal organisation of all of these elements is called duration or rhythm. The quality of a sound is called timbre and varies between kinds and types of instruments, which are tools used to play music. The perceived loudness or softness of a sound is called intensity, often indicated by dynamics.
Writing music
Music can be written in advance of a performance by a composer or songwriter, it may also be "traditional" and handed down "by ear" from individual to individual. Different musical traditions have different attitudes towards how and where to make changes to the original source material, from quite strict, to those which demand improvisation. If the music is written down, it is generally in some manner which attempts to capture both what should be heard by listeners, and what the musician should do to perform the music. This is referred to as musical notation,and the study of how to read notation involves music theory. Written notation varies with style and period of music, and includes scores, lead sheets, guitar tablature, among the more common notations. Generally music which is to be performed is written as sheet music. To perform music then, requires an understanding of both the musical style, and the performance practice expected.
A musician, then, is someone attempting to take material, written down or not, and produce sound which is musical to the listeners. They may be performing music which is close to the source, also called "interpretation", or alternatively the music may be, to a large degree and made up by the performers as they go along (improvisation), though most improvisation is usually within more or less strict boundaries.
Music can also be determined by describing a "process" which may create musical sounds, examples of this range from wind chimes, through computer programs which select sounds. Music which contains elements selected by chance is called Aleatoric music, and is most famously associated with John Cage and Witold Lutoslawski.
Performing music
Music can be performed by a single musician, or several may band together to form a musical ensemble such as a rock band or orchestra. The music they make can be heard through several media; the most traditional way is to hear it live, in the presence of the musicians. Live music can also be broadcast over the radio or television. Some musical styles focus on producing a sound for a performance, while others focus on producing a recording which mixes together sounds which were never played "live". Recording, even of styles which are essentially live often uses the ability to edit and splice to produce recordings which are considered "better" than the actual performance.
After 1960, listening to music through a recorded form, such as sound recording or watching a music video became more common than experiencing live performance. Sometimes, live performances incorporate prerecorded sounds; for example, a DJ uses records for scratching. Of course, you can also create music yourself, by singing, playing a musical instrument, or composing. Modern beginners usually try the guitar or the piano as a first instrument. Many music festivals exist these days celebrating a particular music genre.
Deaf people can experience music by feeling the vibrations in their body; the most famous example of a deaf musician is the composer Ludwig van Beethoven, who composed many famous works even after he had completely lost his hearing. In more modern times, Evelyn Glennie, who has been deaf since the age of twelve, is a highly acclaimed percussionist. See: Baschet Brothers.
Education
People take music lessons when they want to learn to play music. Musicology is a broad field charged with the historical and scientific study of music, including music theory and music history.
Genres
Since music is an ancient art, an extremely large number of musical genres have evolved. Among the larger genres are classical music, popular music (including rock and roll) and folk music. The term world music is applied to a wide range of music with an "ethnic" element. Ethnomusicology is the study of these genres in an anthropological context.
Genres of music are as often determined by tradition and presentation as by the actual music. While most classical music is acoustical in nature, and meant to be performed by individuals, many works include samples, tape, or are mechanical, and yet described as "classical". Some works, for example Gershwin's Rhapsody in Blue is claimed by both Jazz and Classical Music.