A world without sound would be strange and silent. we wouldn’t be able to enjoy music and people would find it difficult to communicate. it would be boring. sound helps us in many different ways. but what is sound.  

how it vibration: IF you tap an object it will vibrate. but it will reflect back and it will come to your ear then throw to your ear drum. It will soon vibrate by shaking your eardrum BACK AND FORTH. THATS HOW OUR EARS VIBRATE BY OUR EARD