system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is volume/sound additive? Like if one person were to scream it would be significantly lower than 100 people screaming at the same decibel level.
gpt
Imagine that you threw a rock into a still pond. It creates waves going out from itself. Now, if you threw two rocks they would each create their own series of waves. When the peaks from two waves overlapped they would create a higher wave than either of the individual ones.

That's what's happening with sound. The sound waves add up and reinforce each other.

Note that there is a sound wave which is exactly the opposite to the original which will completely cancel out both of them. This is the principle behind noise-cancelling headphones.