Suppose I have a closed end aluminum pipe of 3cm diameter with .5cm walls Cylinder is 10cm tall , 8mm of which is submerged in a cold bath of approximately constant temperature of -10°c I feel it with water at 3°c to 7cm height and stick a cork in it. How long till the water freezes? Experimentally it seems like the water freezes from outside in, so I guess its function of the thermal conductivity of the cylinder as well as the thermal conductivity of the outer layer of ice as it freezes inside? Is there a formula relating, I 'd guess heat transfer capacity of the cylinder and of ice, ratio of cold surface area/volume of water, initial temp of cold bath and water, total volume of water Or something like that? Sounds like there's calculus involved of some kind... Many thanks.