History Main / NailsOnABlackboard

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few millimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, in models such as the 2004 Honda Civic, car manufacturers realized that by tuning the plate to mimic the sound of fingernails against a blackboard, the break wear indicator's sound would ''annoy the everliving hell out of the car's owner'' and cause them to hightail it towards the workshop with great haste just to get rid of that nerve-grating sound, thus manipulating the owner into keeping their pads always fresh and preventing accidents caused by poorly maintained brakes.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few millimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, in models such as the 2004 Honda Civic, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the sound the plate produced would ''annoy the everliving hell'' out of the car's owner and cause them to hightail it towards the workshop with great haste ''just to get rid of that sound'', thus manipulating the owner into keeping their pads always fresh and preventing accidents caused by poorly maintained brakes.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few millimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, in models such as the 2004 Honda Civic, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the sound the plate produced would ''annoy the everliving hell'' out of the car's owner who would end up hightailing it towards the workshop ''just to get rid of that sound'', thus manipulating the owner into keeping their pads always fresh and preventing accidents caused by poorly maintained brakes.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few millimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the sound the plate produced would ''annoy the everliving hell'' out of the car's owner who would end up hightailing it towards the workshop ''just to get rid of that sound'', thus manipulating the owner into keeping their pads always fresh and preventing accidents caused by poorly maintained brakes.

* In ''Disney/TheLionKing'', Scar scratches his claws on his cave wall, to the same type of sound.

* In the ''WesternAnimation/WowWowWubbzy'' episode "Bye Bye Birdies," Wubbzy and his three friends must get the La-Dee-Da Birds to move before a snowstorm hits Wuzzleburg. Walden's idea was to make "the worst lullaby ever" with three 'annoying' instruments. Daizy got to play on a blackboard...she wonders how she makes music, before the bear tells her that she's meant to rub her fingers across it. Well, she does trying to even make the lullaby, but then the birds sing and Daizy, alongside Walden and Widget, are put to sleep.

* In one ''ComicStrip/{{Dilbert}}'' strip, a professional UI designer who feels that a "computer interface should hurt the user" adds "fingernails on blackboard" as one of the sounds.

* An early Invention Exchange on ''Series/MysteryScienceTheater3000'' featured the [[MadScientist Mads']] "Chalkman", a record player with a fake hand on the tonearm (with real human fingernails!) played against a chalkboard record in order to compel party guests who are still hanging around at 3 AM to leave.

[[HereComesTheScience Fun fact:]] certain schools of thought posit that the reaction to this sound is an atavistic response to when humanity's pre-evolved ancestors used a similar noise to warn each other of danger that should be fled from at once.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few millimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the sound the plate produced would ''annoy the everliving hell'' out of the car's owner who would end up hightailing it towards the workshop ''just to get rid of that sound'', thus manipulating the owner into keeping their pads always fresh and capable of preventing accidents caused by poorly maintained brakes.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few millimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the sound the plate produced would ''annoy the everliving hell'' out of the car's owner who would end up hightailing it towards the workshop ''just to get rid of that sound'', thus manipulating the owner into keeping their brake pads always fresh and capable of avoiding accidents caused by poorly maintained brakes.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few milimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the sound the plate produced would annoy the everliving hell out of the car's owner who would end up hightailing it towards the workshop just to get rid of that sound, thus manipulating the owner into keeping their brake pads always fresh and capable of avoiding accidents caused by poorly maintained brakes.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few milimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the sound the plate produced made car owners believe that ''their car was falling apart into pieces'' and would hightail it towards the workshop... only to end up finding out that it was just a worn brake pad, thus manipulating the owner into keeping their car always in top condition.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few milimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, car owners suddenly thought ''their car was falling apart into pieces'' and hightailed it towards the workshop... and it turned out that it was just worn brake pads, thus manipulating the owner into always keeping their brake pads fresh and in order.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few milimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, car owners would stop putting off getting fresh brake pads because ''they just wanted to get rid of that goddamn noise'', thus greatly reducing the incidence of accidents caused by worn brakes.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few milimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, car owners would stop putting off getting fresh brake pads because ''they just wanted to get rid of that goddamn noise''.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few milimeters thick, in order to tell the owner via an auditive signal that the brakes are wearing off and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the owners would stop putting off getting fresh brake pads because ''they just wanted to get rid of that goddamn noise''.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few milimeters thick, in order to tell the owner that the brakes are worn and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillennium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the owners would stop putting off getting fresh brake pads because ''they just wanted to get rid of that goddamn noise''.

* The mechanical brake wear indicator found in most modern cars is a metallic plate mounted on the brake shoe that scratches the disc when the brake pad is only a few milimeters thick, in order to tell the owner that the brakes are worn and must be replaced as soon as possible. Sometime around the mid-TurnOfTheMillenium, car manufacturers realized that if they tuned the plate to mimic the sound of fingernails against a blackboard, the owners would stop putting off getting fresh brake pads because ''they just wanted to get rid of that goddamn noise''.

* The 2004 Honda Civic's brake wear indicator ''was specifically designed to sound like this'' to manipulate the owner into hitting the workshop to get new brake pads as soon as possible if only to get rid of that chilling, awful noise.

* In an episode of ''WesternAnimation/BobsBurgers'' parodying ''Film/{{Jaws}}'', Teddy drags his fingers across the board. He has to make the noise himself as he'd just clipped his nails.
* A sketch in Right Now Kapow also parodies the Jaws scene, exaggerating the trope so that ''everyone'' scratches a conveniently nearby chalkboard to say anything, eventually doing it just because it's fun to do. After getting nowhere the Mayor moves to the next subject of discussion, replacing all the chalkboards with whiteboards, which is unanimously denied.

* An early Invention Exchange on ''Series/MysteryScienceTheater3000'' featured the [[MadScientist Mads']] "Chalk Man", a record player with a fake hand on the tonearm (with real human fingernails!) played against a chalkboard record in order to compel party guests to leave at 3 AM.