Sound

 What causes sounds?

Take a walk in the city. Cities are noisy. Car horns honk. Buses and garbage trucks roar by. People talk on the street. It is much quieter in the country. Birds chirp. Cows moo. Water trickles in a creek.

Sounds are everywhere. Some sounds you hear may hurt your ears. You may like other sounds. Each sound you hear is different. Sounds are also alike in some ways.

Sound happens when matter moves back and forth very quickly. This movement is called a vibration. There must be movement to make sound.

The instruments pictured make sounds. They can make high sounds. They can make low sounds. Pitch is how high or low a sound is. Objects that vibrate slowly make a low-pitched sound. Objects that vibrate quickly make sounds that have a higher pitch.

Vocabulary:

horns honk          :            tiếng còi xe

garbage truck      :            xe chở rác

trickles                :            nhỏ giọt

creek                   :            lạch nhỏ

matter                 :            vấn đề

forth                   :             ra ngoài

movement          :             sự chuyển động

pitch                   :             âm độ

vibrate                :             rung

20/8/2021

Levic