Why does the sound of aluminum foil make me cringe? Or even a nail against a chalkboard?

Question

When I simply move aluminum foil out of the oven from like pizza or some chicken alfredo I cringe at the sound of alumimum foil lol I've even tried bitting aluminum foil once and I had the feeling of pain and weirdness together at the same time...hard to explain. Also I cringe at the sound of an evil teacher scratching her nail against a chalkboard lol I wonder why. I would love to know the scientific reasoning behind this greatly appretiate if anyone knows!

Answer 1

they are quite screechy and irritating indeed........no sci reasons but would like to know too.

Answer 2

It's the frequency at which it vibrates that is bothering you.  Most people are bothered by SOME frequency or other that evokes a sympathetic response in the ear, and those happen to be just right for yours.