Sound
Sound intensities can be very different. They can range from 0.000000000001, which are barely heard, to 1 W/m2  (painfully loud). The decibel scale makes sound intensity numbers easier to work with. A 0.000000000001 W/m2 intensity is 0 dB (decibels). It is an exponential scale, so when the decibel number increases by 10, the intensity is ten times as much. So, a 1 W/m2 intensity is 120 dB.