(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A tank of water has been outdoors in cold weather, and a slab of ice 5 cm thick has formed on its surface. The air above the ice is -10C. Calculate the rate of ice formation ( in cm / h) on the ice slab. Take the thermal conductivity of ice to be 0.004 cal / (s.cm.C) and its density to be 0.92 g/cm^3. Assume no energy transfer through the tank walls or bottom.

2. Relevant equations

P(conducted) = Q/t = kA (T2-T1)/ Length

p(density) = m/v

Q = Lm heat of transformation

3. The attempt at a solution

Some thoughts:

When they say on the slab, they must mean underneath it right?

Also they provide standard info the in the question like the conductivity of ice which I could look up in a table. I could similarly look up density and conductivity of water but since they didnt explicidly mention that too, I wonder if I'm not supposed to? Like maybe thats variable in terms of the problem?

Since they arent just asking the rate of conductivity through ice I probably need to use the heat of fusion formulae somewhere too.

So I need to relate the density somehow, in order to cancel out the Area which I dont have.

Pluggin in info for the conduction rate equation I get

P = 0.004A (0--10) / 5

P = A x 0.008

now for density

p = m/v = m/Ah (using A and h cuz I have more information about that, than just V)

0.92 = mA5

I don't see an obvious relation.

(heat of fusion from water to ice = 333)

Q = Lm

Q = 333m

Q = 333 x 0.92/5A

Uhm I don't know where im going with this. I could say both equations are equal to A, but then I still have P and m as variables

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: [thermodynamics] rate of ice formation, -area, +density

**Physics Forums | Science Articles, Homework Help, Discussion**