四年8班 杨星瑶 30号 Sound

Angela（杨星瑶）

Class Eight, Grade Four

No. 30

                                                         Sound

Sound is an amazing thing. It helps us in many ways. But what is sound?

Sound is the waves made by things that vibrate. Its volume can be loud or quiet, and its pitch can be high or low.

How can sound help us?

Sound helps us communicate. Sound can warn us, make signals, and bring pleasure to us. For example, when the traffic lights were broken, the policy would make sounds to make sure we’re safe.

This is sound. What a useful friend to us!