Noise is part of the communication process whether we like it or not. Even in a perfectly predetermined environment like a classroom, noise gets in the way of the direct informational transfer. Imagine a professor saying or showing something on the board at 9:45 am, and precisely at that second when you're trying your best to focus through your lazy and sleepy eyes, the girl sitting next to you decides to open her morning bag of chips, for whatever reason a human being would decide to consume junk food such early in the morning. You are now more focused on the sound of the bag cracking and popping and then the smell of the artifical bacon flavoring than what the professor is trying to communicate to you.
Our team project for the class was to study noise around campus. We decided to go with the question of "Which place on Brooklyn College is the loudest during the start of common hours?" 6 people in our group each went to 6 different locations. I went to probably one of the more boring ones - West Quad. It's a usually low activity place with a few people coming in and out, however during peak it can generate a LOT of noise. For example, right after common hours start is usually when the high school and other campus tours end, and it seemed like a bunch of those tour groups wrapped up in West Quad. The result is about 30 teenagers walking out in loud fashion, no longer controlled by their chaperon, usually being obnoxiously loud in their conversations, bumping into each other and slamming the doors open and closed multiple times.
My West Quad experiment, which lasted a mere 9 minutes and was recorded from 12:30 to 12:39, caught the group walking out right as I started and peaked at 92 dB. That compares to an activated rotary mower. Now, I don't yet know how it compares to my teammates, but I do not wish a group of teenagers as loud as a mower as their backgroud noise.