The Grand Canyon at night has a decibel level of about ___.

• A. 106
• B. 10
• C. 140
• D. 40

Answer: (B)

Sound levels are measured in decibels on a logarithmic scale, so small numeric differences reflect large changes in actual sound energy. A natural place with little human activity, like the Grand Canyon at night, has very low ambient noise—wind, distant water, and faint animal sounds—so the overall level sits near the threshold of hearing. On this scale, that quiet environment is around 10 dB, which is just above the almost inaudible range for a completely silent environment and represents a very soft background sound.

The other numbers describe much louder situations: a loud concert or industrial noise around 100+ dB, and 140 dB is extremely loud and painful to ears. A level around 40 dB is noticeably quiet but clearly audible, like a quiet library. So, the 10 dB estimate best fits the extraordinarily quiet nighttime canyon ambience.