Music:
Music is an art form and cultural activity, and its medium is sound waves (a kind of mechanical waves) organized according to time and law. Its basic elements include strength, tonality, duration and timbre. These basic elements combine with each other to form the common "formal elements" of music, such as rhythm, melody, harmony, strength, speed, mode, form and texture. The formal elements of music are the means of expression of music. Different types of music may emphasize or ignore some elements.