]اجماعة انتوا محيرين نفسكم ليه هى تنتشر بالطريقتين فى الماء كالأتى:
· When a wave spreads in water it spreads as mechanical longitudinal in the deep due to the absence of surface tension force in deep water while as mechanical transverse at the surface due to the presence of large surface tension forces where the longitudinal can't spread in.