3 ms·

> Snow and ice are quite abrasive stuff Per wiki ice has mohs hardness of 2 to 4 depending on temperature and if it has fallen out of the sky I guess it should

by IsTom 2y ago

> Snow and ice are quite abrasive stuff Per wiki ice has mohs hardness of 2 to 4 depending on temperature and if it has fallen out of the sky I guess it shouldn't be mixed with sand or other abrasives. How is it abrasive then?

chrisandchris 2y ago
That assumes that most of the snow is actually fallen from the sky. In central european ski resorts, largest parts of ski lopes are not natural snow anymore (or are mostly mixed natural/artificial). And artificial snow has far more sharp crystals than natural snow.
- IsTom 2y ago
  Shape doesn't matter what the shape is if it's softer than the other material, you can't scratch glass with chalk no matter the shape of it.
  - abakker 2y ago
    minerals in the snow / wind blown grit / rocks / banging around in the ski rack, the lift line, hitting poles, etc. You're right. Snow isn't hard enough, but, it's probably a mistake to assume it's just snow.
  - swader999 2y ago
    I think at a microscopic level, the sharp knife edge on your ski will become rounded after a few runs on ice just from the force involved. You are right, it has little to do with the nature of the snow crystals.
mjhay 2y ago
My guess is two things: 1. All snow has some level of particulates, especially older snow (moreso if there has been melting, because the particles/dirt/whatever concentrate on top). 2. Cornering on piste would put pretty big stresses on the tip of the edge. This could perhaps cause the edge to bend and curl, or even break little pieces off from metal fatigue. I think this would be a bigger deal in most winter skiing conditions.
snthd 2y ago
Above -37, Snow needs particulates to form. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/ice-nuclei https://www.sciencedirect.com/topics/earth-and-planetary-sci... >The most important type of ice nuclei is mineral dusts blown into the atmosphere from deserts, arid lands, and agricultural fields. The International Mineralogical Association (IMA) defines minerals as naturally occurring solid substances formed in geological processes. IIRC snow makers use particulates too.
snowwrestler 2y ago
Moh's scale is useful for field identification of minerals. It's not really useful as an all-purpose predictor of durability. Pressure is a huge variable. In a typical Moh's test, there is very little: just a person rubbing two stones together by hand. But with enough pressure, liquid water (hardness: none) can cut steel. Lead can damage steel or quartz if fired out of a gun. Etc. And as others have mentioned, snow might have particles of other materials in it as well. But just to be clear: Moh's scale does not mean that pure ice could never abrade steel.

by IsTom 2y ago

chrisandchris 2y ago

That assumes that most of the snow is actually fallen from the sky. In central european ski resorts, largest parts of ski lopes are not natural snow anymore (or are mostly mixed natural/artificial). And artificial snow has far more sharp crystals than natural snow.

IsTom 2y ago
Shape doesn't matter what the shape is if it's softer than the other material, you can't scratch glass with chalk no matter the shape of it.
- abakker 2y ago
  minerals in the snow / wind blown grit / rocks / banging around in the ski rack, the lift line, hitting poles, etc. You're right. Snow isn't hard enough, but, it's probably a mistake to assume it's just snow.
- swader999 2y ago
  I think at a microscopic level, the sharp knife edge on your ski will become rounded after a few runs on ice just from the force involved. You are right, it has little to do with the nature of the snow crystals.

mjhay 2y ago

My guess is two things: 1. All snow has some level of particulates, especially older snow (moreso if there has been melting, because the particles/dirt/whatever concentrate on top). 2. Cornering on piste would put pretty big stresses on the tip of the edge. This could perhaps cause the edge to bend and curl, or even break little pieces off from metal fatigue. I think this would be a bigger deal in most winter skiing conditions.

snthd 2y ago

Above -37, Snow needs particulates to form. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/ice-nuclei https://www.sciencedirect.com/topics/earth-and-planetary-sci... >The most important type of ice nuclei is mineral dusts blown into the atmosphere from deserts, arid lands, and agricultural fields. The International Mineralogical Association (IMA) defines minerals as naturally occurring solid substances formed in geological processes. IIRC snow makers use particulates too.

snowwrestler 2y ago

Moh's scale is useful for field identification of minerals. It's not really useful as an all-purpose predictor of durability. Pressure is a huge variable. In a typical Moh's test, there is very little: just a person rubbing two stones together by hand. But with enough pressure, liquid water (hardness: none) can cut steel. Lead can damage steel or quartz if fired out of a gun. Etc. And as others have mentioned, snow might have particles of other materials in it as well. But just to be clear: Moh's scale does not mean that pure ice could never abrade steel.