Decibel
Decibel is a unit that measures how loud or quiet a sound is.
A kitchen scale sits on the counter with two stacks of blocks beside it. One stack has ten blocks and presses down hard, while the other has just one block and barely tips the scale. Each time you add ten times more blocks, the scale reads one step higher. Decibels work the same way, where each step up means ten times more sound pressure.
Explaining decibel by grade level
Some sounds are loud, like cars on a road. Some sounds are soft, like a whisper. We use decibels to count how loud a sound is. A wall can block sound and make the number go down.
Projects that explore decibel
A decibel puts a number on how loud or quiet a sound is, letting you compare noise levels with precision rather than guesswork. In this experiment, digital decibel meters record the sound reaching different distances behind four barrier types — concrete walls, wood fences, earth berms, and rows of trees. The earth berm reduced noise the most at every distance. That finding carries real weight because exact readings let you say "more" or "less" with confidence, not just vague impressions of louder or softer.
The same speaker can produce different decibel readings depending on what surrounds it. You build three sealed plywood enclosures of different depths, mount identical 8-inch speakers in each, and play test tones at six frequencies. A meter placed one meter away records the level for each tone. The larger enclosures produce a flatter response across all frequencies. The smallest enclosure boosts certain mid-range frequencies above the baseline — making some tones noticeably louder than others even though the speaker itself never changes.