Just imaging if people showed similar levels of skepticism around the Mohs scale as the did global warming etc.
The Mohs hardness scale is actually extremely difficult to demonstrate across a full range of natural materials. It’s intuitive that if A scratches B and B scratches C then A should scratch C, but testing a few samples is nowhere near enough to demonstrate across every natural mineral. It’s even more difficult to show this is a stable property that doesn’t very significantly over time.
So, sure a teacher might hand out a few samples and show what the idea is, but that’s little more than hand waving.
> The Mohs hardness scale is actually extremely difficult to demonstrate across a full range of natural materials
Well, sure combinatorial explosion and the difficulty of gathering every possible natural material makes it impractical to show that:
(1) the scale measures a real trait that exhibits the same consistent transitive behavior across all possible combinations of natural materials, and
(2) every natural material with a rating on the scale is correctly rated.
It's relatively easy to establish that the set of standard examplars for the integer ratings consistently show the relative properties the scale is supposed to measure.
Of course, it trivial to then verify the same is true relative to the examplars for any other material with an established rating, or to establish (within the bounds of the ceiling/floor integers) the rating of any material for which one doesn't have a measure and confirm consistency against examplars and any manageable sample of other rated materials.
The Mohs hardness scale is actually extremely difficult to demonstrate across a full range of natural materials. It’s intuitive that if A scratches B and B scratches C then A should scratch C, but testing a few samples is nowhere near enough to demonstrate across every natural mineral. It’s even more difficult to show this is a stable property that doesn’t very significantly over time.
So, sure a teacher might hand out a few samples and show what the idea is, but that’s little more than hand waving.