When will hot water cool down more slowly?

Question

Take an equal volume of hot water at similar temperatures in two similarly shaped containers- one made of glass and the other made of steel. In which container would the water cool faster and why?

Take an equal volume of hot water at similar temperatures in two similarly shaped containers- one made of glass and the other made of steel. In which container would the water cool slower and why?

Answer 1

The coefficient of thermal conductivity for steel is 0.00015, and of glass is 0.000002 gram-calories per per sq. cm. per cm. per degree centigrade therefore the steel is a much better conductor of heat and will cool down the water the fastest.

Answer 2

The water won't necessarily cool down at all. If the water is at 160F, for instance, and the containers are in 200F oil, the water will heat up. If surrounded by cold air, however, the water will cool down.

In either case, the water will change temperature faster in the steel container, assuming that the steel and the glass are not only similarly shaped, but of similar thickness as well.

The thermal conductivity of glass is 1.05. The thermal conductivity of garden variety steel is 46. That means the steel is a better conductor.

As a rule, better thermal conductors are are better electrical conductors as well. If that had been a copper container, it would have cooled down even faster. (If you've seen skillets that were copper on the bottom, that's why - it makes the cooking more even.)

Glass doesn't conduct electricity at all, in practical terms, and it's pretty good as a thermal conductor as well. It takes longer to chill a bottle of beer than a can - but takes longer to warm up as well, which is one reason why people who like the taste of beer (as oppose to those who drink just to get drunk) tend to buy beer in those thick long-neck glass bottles, rather than the thinner disposable beer bottles or aluminum cans.

Answer 3

This is a Newton's Law of Cooling type problem. Newton said that the rate of cooling from a body is proportionate to the temperature difference between that body and the surrounding fluid (for a convective type situation). The proportionality constant is the heat transfer coefficient. This coefficient can be built from a series of resisitances, and will be much higher (more heat transfer) for the steel vessel. Since we don't know anything about the heat transfer from the surface, it is probably best (at least at first pass) to assume adiabatic transfer from this surface (very little if any heat transfer).

Answer 4

The surrounding ambient temperature amd humidity is to be specified since water will cool by evaporation from its surface also apart from conduction thru the wall .
Initially , water in steel container will cool faster due to greater heat conduction to outer surface and radiating therefrom .
Later as temperature goes down near to surrounding temperature , latent heat taken from water by the vapour formed at the water/air interface is the dominant heat transfer mode .and cools the water about 2.5 deg.C lower than the surrounding and then becomes stable . During that phase water in glass vessel will cool faster .

Answer 5

If you said Copper instead of Steel i would say Copper...

The metal conducts heat better than glass...

Answer 6

I think metal would cool faster because it isn't as great as an insulator as glass. I'm not 100% sure.

Answer 7

-the one in the glass will cool faster
it allows easier heat transfer to the outside

-has to do resistance and correct me if im wrong the specific heat capacities of the materials
glass = 0.84
steel = 419-503

Answer 8

Steel. Better conductor, therefore better radiator.