1. The problem statement, all variables and given/known data Hi everyone. I watched a YouTube video earlier today which said that sound waves travel faster in more dense mediums. For example, sound travels faster in water than it does in air. However, on this webpage http://www.physicsclassroom.com/mmedia/waves/ltm.cfm it says that "the wave speed is always greatest in the least dense medium". So which is true? 2. Relevant equations 3. The attempt at a solution I am thinking that maybe it depends on the type of wave, and that transmitted/reflected waves work differently than sound waves.