Because the hot coffee at the bottom of the vessel, is brought more rapidly in contact with the air, and, therefore, gives off its heat more rapidly.
Why does blowing hot coffee cool it quickly?
Because the hot air over the coffee is removed by blowing, and the cold air is brought more rapidly in contact with the coffee.
Liquefaction.
Is ice a solid or a liquid?
Ice is a solid.
When heat is applied to ice, what becomes of the ice?
The ice is changed into water.
Is water a liquid?
Water is a liquid.