I don't understand, ice, water, freezing,drying?

[organicguy]

Freezing hard every night, barely thawing.
Dry ground, hard as rock.
Farm track, ice over puddles, 5mm thick, driven over and broken, ice again but still water in the puddles?
Wet field, trodden by cattle in autumn, ice 5mm thick, gap of 50mm, then water in the bottom of the foot mark. Is that water coming out of the ground and being dried away before it freezes?
I cannot believe its not solid as a rock?

 

[TWF]

Freezing hard every night, barely thawing.
Dry ground, hard as rock.
Farm track, ice over puddles, 5mm thick, driven over and broken, ice again but still water in the puddles?
Wet field, trodden by cattle in autumn, ice 5mm thick, gap of 50mm, then water in the bottom of the foot mark. Is that water coming out of the ground and being dried away before it freezes?
I cannot believe its not solid as a rock?

I imagine you are on about Latent heat. When water freezes it gives off a little heat so that's why you still have unfrozen water. Each nights frost will freeze deeper.
To protect apple orchards years ago from frost the would spray irrigate them and the water would freeze on the trees and protect them.

 

[Kidds]

To protect apple orchards years ago from frost the would spray irrigate them and the water would freeze on the trees and protect them.

They still do.

 

[Bloders]

water is a unique liquid.
1) as it cools below 4 degrees C it expands. I dont believe any other material expands as it cools
2) as a liquid, it freezes from the surface down/ if water behaved like other liquids, instead of getting a frozen layer on top, the whole lot would go solid - imagine that in lakes etc - everything would die and life would cease.

Water is VERY special in so many ways.

 

[DrWazzock]

Ice also can go straight to the vapour state without passing through the liquid phase. Fascinating substance. It’s a wet planet, as my chemistry teacher said.

 

[ARW]

water can remain a liquid when frozen, as it needs room to expand to freeze, so a big lake with water at the bottom cannot freeze with the pressure of the water above

 

[deleted user 837354]

Being less dense, the layer of ice probably insulates the water below I would assume? I know they always said snow insulates the crop below?

 

[Cab-over Pete]

It does, and it’s a pain in the arse and the reason I’ve not turned a wheel in these past two sharp frost mornings.
Maybe 75% of the planted ground I would like to get spread with fibrophos would travel quite well, but as soon as you see a bit of snow the ground beneath it isn’t firm enough.
I need frost before snow, not the other way round.

 

[Forever Fendt]

Looks like some on here know what there talking about so a quick question ,If we have fresh snow fall on a building roof is it going to continually get heavier as the days go by if we keep getting hard frosts after the snow as most buildings don't seem to collapse straight away

 

[Bloders]

Ice also can go straight to the vapour state without passing through the liquid phase. Fascinating substance. It’s a wet planet, as my chemistry teacher said.

I did not know this. i always thought it was only CO2 whihc could sublime.

 

[Sid]

It does, and it’s a pain in the arse and the reason I’ve not turned a wheel in these past two sharp frost mornings.
Maybe 75% of the planted ground I would like to get spread with fibrophos would travel quite well, but as soon as you see a bit of snow the ground beneath it isn’t firm enough.
I need frost before snow, not the other way round.

Hence why the Canadians like a layer of snow over their crops before it freezes.

 

[TWF]

Looks like some on here know what there talking about so a quick question ,If we have fresh snow fall on a building roof is it going to continually get heavier as the days go by if we keep getting hard frosts after the snow as most buildings don't seem to collapse straight away

I'm no engineer but in the day time the snow will slump a little if the day warms up and melt a little. This may move an evenly distributed load into more of a point load, adding more weight to the middle of the roof at the weakest point?

 

[Exfarmer]

water is a unique liquid.
1) as it cools below 4 degrees C it expands. I dont believe any other material expands as it cools
2) as a liquid, it freezes from the surface down/ if water behaved like other liquids, instead of getting a frozen layer on top, the whole lot would go solid - imagine that in lakes etc - everything would die and life would cease.

Water is VERY special in so many ways.

lakes freeze Fromm the surface due to that being the exposed part. They will freeze completely through if the air temperature is low enough and long enough. but protection comes due to the insulation value of the ice and the ground heat.
Also to lose 1 degree C. a gram of water has to lose 1 calorie.
To change from water at 0c to ice at zero c that gram of water has to lose 80 calories

 

[Exfarmer]

Looks like some on here know what there talking about so a quick question ,If we have fresh snow fall on a building roof is it going to continually get heavier as the days go by if we keep getting hard frosts after the snow as most buildings don't seem to collapse straight away

No nothing gets heavier with time unless more snow falls

 

[Kiwi Pete]

I did not know this. i always thought it was only CO2 whihc could sublime.

A few things do; mostly it's to do with their vapour pressure within common temperature ranges as to whether it is noticeable, I think?

Many simple turpenes will, the other one we used to play with in the science lab was Iodine.

eg in a mothball, there's camphor and p-dichlorobenzene and they both undergo sublimation (one vapour brings them, the other one kills them)

 

[Kiwi Pete]

No nothing gets heavier with time unless more snow falls

Or rain, which is what kills roofs around here under snow loading, because it turns the dry (light) snow into a big wet (heavy) sponge

 

[deleted user 837354]

I understood CO2 frozen would sublime- there is no liquid phase involved?

 

[primmiemoo]

Sublimation is ancient magic!

 

[Kiwi Pete]

Sublimation is ancient magic!

Can't beat some purple smoke

 

[Exfarmer]

Sublimation is ancient magic!

Not sure how thry got hold of the liquid CO2 though