Going to high school with a bunch of pranksters had its ups and downs but one of the more memorable moments was in my chemistry class my sophomore year. A few of my classmates had the "mosquito" ringtone on their phones and decided it would be fun to play it. All of the students in the class heard it and thought it was funny but the older teacher couldn't hear a thing. The interesting thing about this was that there was a TA in the class helping out and he could hear it. Eventually he got sick of it and let the teacher know. He then confiscated all of our phones, even the people who weren't involved.
To me the fact that the TA could hear the noise but the teacher couldn't was weird. At the time I thought it was a sound that no adult could hear and to me the TA was an adult. I later found out it is after a certain age that a person becomes unable to hear it. After taking this introductory psychology class I started wondering if this phenomenon was purely because of a physical change as we get older or because of something else like our conscious changing. I really want to learn more about this and research it to see if I can find an answer.