Physics question - melting snow

[Bowler]

One for the clever people...

Why has the snow melted on my patio/drive, but not on my lawn or wooden patio furniture?

Huh?

[350GT]

Concrete/tarmac hold heat better?

[Allanv]

wild stab in the dark.

the cold has penetrated deeper (staying longer) into the furniture and grass than it could into the concrete.

[mybrainhurts]

Your urine is warmer than anything else out there...

[LD1Racing]

In simpe terms, different surfaces/materials heat up and cool down at different rates, so as the temperature rises, the (stone) warms up quicker than the (frozen) lawn.

[Allanv]

mybrainhurts said:

Your urine is warmer than anything else out there...

An answer based on user name very good...

[Bowler]

Allanv said:

mybrainhurts said:

Your urine is warmer than anything else out there...

An answer based on user name very good...

Ok, But would paving slabs and a block drive retain heat (however little) for so long?

BTW, I only piss on my neighbours lawn - his is clear.

[350GT]

I think they would retain it for longer than the ground would... hence possibly melting quicker.

[Crimson Tide]

Albedo?

Edit: No. I think that's to do with absorption of sunlight.

Edited by Crimson Tide on Wednesday 4th February 21:08

[GreenV8S]

Ground is warm, but soil is a good insulator so you only have to cool down the top inch or so to get it to freeze. Concrete is a much better conductor so you have to cool more of it down to get the top bit down to freezing, and the thermal mass of the deeper bits will keep trying to thaw it again. It you kept it cold for long enough so you got it all freezing a foot or so down you'd probably notice the reverse effect with the soil warming up quicker.

[fido]

Yep, same reason why the snow on your car melts first, metal is a good conductor - and snow stays longer on a well-insulated roof.

[Bowler]

GreenV8S said:

Ground is warm, but soil is a good insulator so you only have to cool down the top inch or so to get it to freeze. Concrete is a much better conductor so you have to cool more of it down to get the top bit down to freezing, and the thermal mass of the deeper bits will keep trying to thaw it again. It you kept it cold for long enough so you got it all freezing a foot or so down you'd probably notice the reverse effect with the soil warming up quicker.

fido said:

Yep, same reason why the snow on your car melts first, metal is a good conductor - and snow stays longer on a well-insulated roof.

Cheers guys: I knew that clever people would answer this question.

GreenV8S - Nice car!