The effects of sound and music are quite interesting. It is obvious that sound travels through air, liquid and even solid substances. People do not often think, though, about how sound travel through bodies as well. Music has the power to effect how we feel, our attitudes and so much more. Some sounds can put people to sleep. Some help with meditation. Others helps to jolt the nerves and alert people. It is also obvious that music can affect peoples' emotions. There are even careers that aid people by means of music. According to musictherapy.org, "Music Therapy is the clinical and evidence-based use of music interventions to accomplish individualized goals within a therapeutic relationship by a credentialed professional who has completed an approved music therapy program." It's a fun experiment to try to pay attention to what you are listening to and how it affects you. I've found that some of the hard core and metal music that I listen to gets me easily angry or in an on edge mood, and that some of the soft acoustic music can help settle me down. A fire siren puts my body on alert and birds chirping is calming to wake up to. There have even been studies done as to how the tempo and key affect certain parts of one's body. It just amazes me that there is so much depth to sound and that it can have such an effect on people.