The Naked Scientists

The Naked Scientists Forum

Author Topic: what produces the chalk on a chalk board noise  (Read 3763 times)

paul.fr

  • Guest
what produces the chalk on a chalk board noise
« on: 07/08/2007 22:54:31 »
One of the things i don't miss about school, is the noise made by the teacher whilst using the chalk. But why does it make such a terrible noise?

Aslo, changing the angle of the chalk produces different pitches, why is that?


 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
what produces the chalk on a chalk board noise
« Reply #1 on: 08/08/2007 19:19:58 »
One of the things i don't miss about school, is the noise made by the teacher whilst using the chalk. But why does it make such a terrible noise?

Aslo, changing the angle of the chalk produces different pitches, why is that?
It should be because of the high frequency vibrations produced by the chalk accelerating/stopping many times every second on the board, because of friction. The amplitude and frequency of those vibrations depend on many factors: mass, consistence, shape, dimensions, angle, of the chalk (at constant properties of the board).
 

Offline kdlynn

  • Neilep Level Member
  • ******
  • Posts: 2851
    • View Profile
what produces the chalk on a chalk board noise
« Reply #2 on: 08/08/2007 20:07:03 »
i always liked the chalk noise. didn't like the fingernails on a chalk board noise.. but the chalk was ok
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
what produces the chalk on a chalk board noise
« Reply #3 on: 08/08/2007 21:04:51 »
i always liked the chalk noise. didn't like the fingernails on a chalk board noise.. but the chalk was ok
But I assume paul.fr intended that horrible, high-pitched whiz it makes sometimes when the chalk is still long.
 

paul.fr

  • Guest
what produces the chalk on a chalk board noise
« Reply #4 on: 08/08/2007 21:41:11 »
i always liked the chalk noise. didn't like the fingernails on a chalk board noise.. but the chalk was ok
But I assume paul.fr intended that horrible, high-pitched whiz it makes sometimes when the chalk is still long.

You assumptions, are correct. ;D
 

Offline kdlynn

  • Neilep Level Member
  • ******
  • Posts: 2851
    • View Profile
what produces the chalk on a chalk board noise
« Reply #5 on: 08/08/2007 23:07:32 »
oh i see.
 

Offline _Stefan_

  • Hero Member
  • *****
  • Posts: 814
    • View Profile
    • My Photobucket Album
what produces the chalk on a chalk board noise
« Reply #6 on: 09/08/2007 07:24:18 »
Every time I read the topic heading of this thread I get shivers down my spine. I hate the screech of chalk and fingernails on blackboards!
 

Offline dentstudent

  • Neilep Level Member
  • ******
  • Posts: 3146
  • FOGger to the unsuspecting
    • View Profile
what produces the chalk on a chalk board noise
« Reply #7 on: 09/08/2007 07:28:24 »
Strangely, this noise doesn't bother me at all. What I don't like is the sensation of drying a wooden spoon on a teatowel. It makes me clench my cheeks just thinking of it! Also, that accidental grinding of your teeth that squeaks.
 

Offline kdlynn

  • Neilep Level Member
  • ******
  • Posts: 2851
    • View Profile
what produces the chalk on a chalk board noise
« Reply #8 on: 09/08/2007 07:52:21 »
i don't like the sound of terra cota pots rubbing together. or touching them... or spelling the name right....
 

The Naked Scientists Forum

what produces the chalk on a chalk board noise
« Reply #8 on: 09/08/2007 07:52:21 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums