Knife blade physics

B

bryan123

Joined
Feb 7, 2017
Messages
264
I've been wondering about this.

At the very edge of a sharp blade, how many atoms width are we talking about? Tens? Hundreds? Thousands?

Thanks
 
Probably better to use microns as a unit of measure, as atoms aren't a single uniform size and, since we're dealing with molecules, aren't real helpful anyway. Even then, I suspect it would be really difficult to accurately measure.
 
You can't get a definite answer because the width of a sharp apex varies quite a bit, say from 0.5 to 1 micron.

And the diameter of an atom is not easy to calculate, either, because there is no easily defined outer boundary of an atom.

But if you say a really sharp apex is 0.5 microns wide, you can get an idea. 0.5 microns is 500 nm. An atom of iron is about 140 picometers, or 0.14 nanometers in diameter. So you could have 3,571 iron atoms side by side across the entire apex of a sharp edge that is half a micron wide.
 
What he said
Twindog said:
You can't get a definite answer because the width of a sharp apex varies quite a bit, say from 0.5 to 1 micron.

And the diameter of an atom is not easy to calculate, either, because there is no easily defined outer boundary of an atom.

But if you say a really sharp apex is 0.5 microns wide, you can get an idea. 0.5 microns is 500 nm. An atom of iron is about 140 picometers, or 0.14 nanometers in diameter. So you could have 3,571 iron atoms side by side across the entire apex of a sharp edge that is half a micron wide.
Click to expand...
 
Insipid Moniker said:
Probably better to use microns as a unit of measure, as atoms aren't a single uniform size and, since we're dealing with molecules, aren't real helpful anyway. Even then, I suspect it would be really difficult to accurately measure.
Click to expand...

Molecules of what?
 
Dependent on carbide size I'd guess, but you're not gonna have an edge that is a countable amount of 'atoms' thick any time this century, or next.
 
Depending on what you mean by "sharp" and "at the very edge", I suppose it could be an elementary particle or fundamental particle. In particle physics, an elementary particle or fundamental particle is a particle not known to have any substructure, thus it is not known to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which all other particles are made. In the Standard Model of particle physics, the elementary particles include the fundamental fermions (including quarks, leptons, and their antiparticles), and the fundamental bosons (including gauge bosons and the Higgs boson). Although elementary particles are not made up of smaller particles, some of them may change to lighter particles (according to specific rules). Yeah, I plagiarized.
 
Atoms and molecules are extremely small in relation to the much coarser crystalline structure of steels. The granularity of the crystals will limit apex radius long before you get down to atomic scale. Now if you want really sharp edges, glass is the way to go because it lacks the crystalline structure found in metals. Obsidian (a naturally occurring glass) is used for tiny neurosurgery scalpels for this reason.
 
Bill1170 said:
Atoms and molecules are extremely small in relation to the much coarser crystalline structure of steels. The granularity of the crystals will limit apex radius long before you get down to atomic scale. Now if you want really sharp edges, glass is the way to go because it lacks the crystalline structure found in metals. Obsidian (a naturally occurring glass) is used for tiny neurosurgery scalpels for this reason.
Click to expand...
Only for veterinary use, however.
 
You must log in or register to reply here.
Back
Top