How do "decibels" work (in an easily, layman's understandable way)?

Factual Questions
1

What I am really after here is an easy and understandable way to describe decibels to someone else without a lengthy description. I know decibels is a logarithmic scale but I am hard pressed to say what that means in real world terms.

If I am at a concert and the decibels are 100 what would it mean if it was (say) 80?

20% (1/5) less? 4x less? What is 4x less if expressed as a percentage? I know this might be nonsense (if not I lucked into a right answer) which is why I am asking.

Ideally, I’d like an answer that is easily digestible to anyone and not some science level answer (well…both would be cool).

2

You are asking about perception, which also depends on frequency and a host of other factors. The rule of thumb is 10 dB = “twice as loud”

so 80 dB is 1/4 as loud as 100 dB

Usually people give examples, e.g., a normal conversation might be at 60 dB