My team mates and I were talking recently about what sounds we loved to hear while we were playing. most of the time we talked about how we could never hear our coach yelling at us from the side line, or how the sound of the ball against the back board of the cage was our worst or favorite sound depending on who scored. We also know the pain caused by the sound of two sticks hacking against each other. Sound is produced by air particles moving through a medium that cause a vibration that our ears recognize as noise. The brain then associates those sounds with pleasure or any other type of emotion experienced when you witness that noise. These sound waves require a medium to travel through in order to make the noise that we recognize. This is known as a longitudinal wave.