The Thermodynamic Definition of Heat

What happens when you leave a cup of ice water in a room at 25oC?
What happens when you leave a cup of hot tea in a room at 25oC?
  • The ice will melt and then the water will get warmer.
  • The hot tea will get cooler.
  • This will continue until both liquids reach room temperature.

Heat

:
Energy in transition from one object or system to another driven by a temperature difference between the objects or systems.

Cup of
ice water

Cup of water.
Heat exchange arrow

Cup of
hot tea

2 kJ
heat
Surrounding Air
Cup of water.

Ch4, Lesson B, Page 1 - The Thermodynamic Definition of Heat