Home / Topics / Heat & Thermodynamics
Heat
Beginner
Energy in transit due to temperature difference.
Heat is energy transferred between bodies due to a temperature difference, measured in joules. A body has internal energy, not heat.
A hot pan loses heat to the air.
Don't say a body "contains heat".
In more detail
Heat is energy transferred between systems because of a temperature difference. It flows from hot to cold and stops when temperatures are equal.
Real-world uses
- Heating a room transfers energy from a radiator to the air.
- Cooking transfers heat from the pan to the food.
- Hot soup on a table transfers heat to the cooler air and the table, which is energy moving because of a temperature difference.
Open the interactive lesson, with simulation and quiz →
Frequently asked questions
Does a body contain heat?
Bodies contain thermal energy. Heat describes the transfer of that energy.
What is the unit of heat?
The joule, the same as other forms of energy.
Can an object contain heat?
No. Heat only exists as energy in transit, so it is better to say an object contains internal energy.
Related topics in Heat & Thermodynamics
Thermal expansion · Area and volume expansion · Anomalous expansion of water · Specific heat capacity · Molar heat capacity · Latent heat