A sound is louder when the vibrations are bigger. The volume of a sound is how loud or soft it is.
A decibel (dB) is the unit we use to measure the volume of sound.

These are the volumes of some everyday sounds. Very loud sounds (louder than 85 dB) can damage our ears.

Some people play loud music. How can you find out how loud the music is? You can use a sound level meter.
You will need: a sound level meter - ways to make different sounds
Think of some sounds to measure, for example, clapping hands, blowing a whistle, slamming a door or the class talking. Predict which sound will be loudest and which will be softest. Plan how you will measure the sounds. How will you make sure that the test is fair? Plan how you will record the sounds. Will you use a table or a bar chart?

1) Predict the volume of silence in decibels.
2) How can you find out if your prediction is true?
1) Which sound was loudest?
2) Which sound was softest?
3) Were your predictions correct?
4) Explain why some sounds are loud and other sounds are soft.