Sound is produced by my instrument by the wave traveling though the bottle and dispersing before finally interacting with the water. You would change the pitch either by changing the shape of the bottle or the distance between the water and the point it is being stricken from. I will be using water bottles filled with precise amounts of water set to 5 musical keys. It will be played by striking the top of the bottle and making the sound reverberate though out the bottle. My plans for construction it are simply acquire water bottles and fill them with set amount of water. This instrument is rather simple and I have no outstanding questions about it.