Melting ice Rates Under Pressure
Most recent answer: 10/22/2007
Q:
Would an ice with a heavy object on top melt faster than an ice with nothing on top?
- morris fung
New York , NY, USA
- morris fung
New York , NY, USA
A:
The answer is: probably yes, a block of ice being compressed should
melt faster than another block of ice, with *all other variables in the
problem held equal* (air temperature, air flow rate, humidity, what’s
under the ice and its temperature, and, quite imporatantly, you have to
put something on top of your control ice block which isn’t heavy, but
has the same thermal properties -- it could even be the same heavy
object, but with some of the weight lifted with a spring or something).
The melting temperature of ice is a bit lower when the ice is under pressure -- you can read up on this fascinating effect in other questions and answers on this site. The block of ice will then be melting at a lower temperature. It takes the same amount of heat energy to melt a gram of ice, 80 calories per gram, whether the ice is under pressure or not. The question of which melts faster is a question of which ice block has heat energy transferring to it faster.
Heat flows from hot objects to cold ones. The rate at which heat flows is directly proportional to the temperature difference of the two objects. Given the same air temperature, heat should flow into a colder block of ice faster than a warm block of ice. The unpressurized block of ice sits at 0 degrees Celsius while it melts, and the pressurized one will have a lower temperature, so it receives the heat energy faster and melts faster.
Tom
The melting temperature of ice is a bit lower when the ice is under pressure -- you can read up on this fascinating effect in other questions and answers on this site. The block of ice will then be melting at a lower temperature. It takes the same amount of heat energy to melt a gram of ice, 80 calories per gram, whether the ice is under pressure or not. The question of which melts faster is a question of which ice block has heat energy transferring to it faster.
Heat flows from hot objects to cold ones. The rate at which heat flows is directly proportional to the temperature difference of the two objects. Given the same air temperature, heat should flow into a colder block of ice faster than a warm block of ice. The unpressurized block of ice sits at 0 degrees Celsius while it melts, and the pressurized one will have a lower temperature, so it receives the heat energy faster and melts faster.
Tom
(published on 10/22/2007)