Changing the volume of sound

What is this?

What is this?

The microphone, the amplifier and the loudspeaker make a ___. It make the sound ___

What kind of variable are they?

Mike are testing the loudness of clock sound through some materials. The materials consist of wood, paper, orange juice, carbonic gas in a balloon. The materials are

What is the best material for sound to travel through?

Rearrange the letters to get a correct word:

fumefl

Rearrange the letters to get a correct word:

lisencre

Arrange the words to have a correct sentence:

wear/ in/ place./Workers/ear/sound/defenders/muffle/to/noisy

We fit ___ to cars, trucks and motorbike to muffle the sounds of their engines.