Some things you might want to think about:

Which sounds are the loudest and which are the quietest?

Why are some sounds louder than others?

How would it affect our daily life?

What could you do to muffle sound to make it quieter or amplify it to make it louder?

Why?

Loud noises are carried by sound waves that have a higher amplitude (height between peak and trough) than quiet noises. The volume of sound decreases as you move further away from its source, because as sound waves travel away from their source the same amount of energy is spread over a greater area, so the intensity and loudness of the sound decreases.

Loudness is measured on the decibel scale. The quietest sound human ears can detect provides the starting point on the decibel scale of 0 dB. A whisper is about 30 dB, and the loudest a sustained sound can possibly be on Earth’s surface is 194 dB. One of the loudest ever sounds recorded was the eruption of volcano Krakatoa in 1883. It created a sound wave which registered 180 dB and was so loud it was heard 3000 miles away. Extremely loud rock music can reach an intensity of 120–140 dB, which is loud enough to cause temporary or permanent damage to hearing. Humans can scream quite loudly too; the world record registering 129 dB.

If we lived in a world where every sound was loud, we would need to adopt ear protection. There are some people who routinely need to do this as their working environment is so loud. If you work outside at an airport, you need ear defenders as noise from a jet can reach a volume of 140 dB. Equally, if we lived in a world where every sound was quiet, we would need to adopt ways of amplifying sound. Hearing sound at different volumes is an essential part of our existence. Communication involves speaking at different volumes reflecting what we are saying. Our lifestyles depend on different volumes of sound for different activities, such as sleep or listening to music in a concert hall. We normally experience everyday sound anywhere on a scale from 0 dB to 85 dB.