Chapter 13 wave motion and sound 813-2 Wave Types p327-331 Classification According to Natures of Matter 1. Mechanical waves 机械波:机械振动以一定速度在弹性介质中由近及远 地传播出去,就形成机械波。 Such as water waves, sound waves all these waves have certain central features: they are governed by Newtons laws, and they can exist only within a material medium(媒质、 介质), such as water,ai, and rock.Chapter 13 Wave Motion and Sound Classification According to Natures of Matter §13-2 Wave Types p327-331 1. Mechanical Waves 机械波: 机械振动以一定速度在弹性介质中由近及远 地传播出去，就形成机械波。 Such as water waves, sound waves. All these waves have certain central features: they are governed by Newton’s laws, and they can exist only within a material medium（媒质、 介质）, such as water, air, and rock