The Sound of Screech
Ashley Lopez
Honors Physics- Block 2

Ever cringed at the sound of someone scratching a chalkboard?   You are not the only one that has.   Researchers became curious as to why this actually happens and conducted an experiment. It is in fact not the lowest or highest sounds in the squeak that makes ones skin crawl, it is actually the tones in a range on a piano keyboard.   This is so because the hearing of a human has trained itself to be sensitive to these tones.   Researchers also found that most people find discomfort knowing that it comes from a chalk board instead of thinking that it came from an orchestra.   In other words, most people would not find the sounds as discomforting if the people thought it came from something as nice sounding as an orchestra.   A visual scientist also states that seeing a person actually scratch a chalk board will increase discomfort.   Most people would still feel discomfort watching it while even taking out the sound.
To discover which frequencies are the ones that cause such chilling noises, the researchers conducted an experiment. The experiment consisted of 6 different chalk board squeaks.   These were played to 104 unfortunate people.   The people would then rate their level of discomfort while listening to these different tones.   The researchers measured changes in 24 listeners’ vital signs and skin conductivity which are indicators of stress.   This was while replaying the two most annoying clips.   The clips reached all the way up to 12,000 hertz or more. Removing both the highest and lowest did not make much of a difference.   Removing all tones between 2,000 and 4,000 did make the experience better.
This experiment proved one great question.   I had always wondered what made people cringe at such a thing.   This helped me along with others to obtain a better understanding of why this is so.   I feel that we could benefit from such a study because not only did it answer one question, it could lead us...