hi, It is a bit confusing, because when I say "wave equation" the connotation it invokes in my mind is if I apply the equation I will find the function of the wave I'm exploring. Of course I know now this is wrong.. it is the other way around, I have to know my wave-function in advance and substitute it into the "wave equation". Tell me if so far I'm on the right track ? My next question is what do I get back ? I can see there second-partial-derivative of position OR second-partial-derivative of time, but what is their meaning.. what is the idea ? For example in the Newton law I can understand the second-derivative of position against time is acceleration, but in the wave equation we have second-partial-derivative of position against "frozen"-time , what does this mean ? And then similar for time ? Help me make the connection, thank you ?