Music is one of the few things that has remained constant throughout the centuries this world has existed. Music not only provides entertainment but also has several effects attached to it. Music allows emotions of happiness and sadness to arise. Those emotions can result in physical effects, negative or positive. Music has a profound effect on the emotional, social, intellectual and physical aspects of a person. Emotions are easily influenced by external forces. Music can evoke emotions of sadness, grief, joy, and even ecstasy. There are several aspects of music that change the way a song is interpreted. Emotions arise from these interpretations. Among these is tempo, which is the speed of the song. If a song is sad, the tempo is often slower. If a song wants to be happy, the tempo is fast and light. If the intention of a song is to inspire fear, it is either extremely slow and disturbing or fast and adrenaline-filled. Another factor of interpretation is the key it is in. A key is "a particular scale or system of tones" (Dictionary.com). There are 24 different keys divided into two categories. These categories are major and minor. The major is made up of multiple sharps and the minor is made up of multiple flats. The major key is used to express feelings of joy and happiness. The minor key, however, is used to express feelings of sadness, depression, and regret. When the two are combined awkwardly, the key of the music changes to neither minor nor major and is called dissonance. A dissonance is defined as “a simultaneous combination of tones conventionally accepted as being in a state of unrest and in need of completion” (Dictionary.com). When a musical passage uses dissonance, the ultimate goal is to create...... middle of paper......www.cerebromente.org.br/n15/mente/musica.html>.Savill, Agnes. "Music and Letters". Physical effects of music. Np, nd Web. 14 January 2012. .UCP, . “Benefits of Music for Children with Special Needs: Tips for Parents and Educators.” United cerebral palsy. Np, 2012. Web. 12 January 2012. Vaidya, Geetanjali. "Music, emotions and the brain". Serendip. Np, 2004. Web. Jan. 7, 2012. Weir, Kirsten, and Debbie Nevins. "Music and your mind... (cover story)." Current Health Kids 34.1 (2010): 10-12. Health Source - Consumer Edition. Network. January 9, 2012. Wicke, Roger W. . “Rocky Mountain Herb Institute.” Effects of music and sound on human health. Np, 2002. Web. 14 January 2012.