matter is made of particles & air is a kind of matter -> land is a energy made of land solid air is a matter made of air particles  air is a matter made of air particles & sound requires matter to travel -> vision can staying_put through land sound can travel through air  vibration is a kind of motion & something requires rest to staying_put -> something can travel by vibrations something can travel by vibrations  sound can travel through air & something can staying_put by needle -> sound can travel through air by vibrating air