Thermal equilibrium — Science definition
Defined in 2 courses:
- A state in which interacting objects have the same temperature. (Physical Science: Matter, Forces & Energy)
- The state reached when two objects in contact reach the same temperature and heat stops flowing between them. (Physical Science: Matter, Forces & Energy)
Where it is taught
- Temperature & Thermal Energy — Phases of Matter, Physical Science: Matter, Forces & Energy, Grade 8
- Thermal Energy & Heat Transfer — Energy & Heat Transfer, Physical Science: Matter, Forces & Energy, Grade 8
In use
In an insulated system, transfer continues until the objects reach thermal equilibrium: the same temperature.
Temperature & Thermal Energy
When objects can exchange energy without continuing external heating or cooling, they can approach thermal equilibrium: equal temperature and no net heat transfer between them.
Thermal Energy & Heat Transfer
Questions using thermal equilibrium
Problem 1
Thermal equilibrium means interacting objects have the same…
- mass
- volume
- temperature
- number of particles
Answer and explanation
temperature
At equal temperature there is no net heat transfer between them.
Problem 2
A 25°C metal spoon is placed in 80°C soup. They reach thermal equilibrium at 65°C. By how many degrees did the spoon's temperature change?
Answer and explanation
40 °C
Temperature change = 65 − 25 = 40°C.
Problem 3
Two objects are placed in contact: one at 90°C, one at 30°C. They reach thermal equilibrium at 60°C. By how many degrees did the cooler object's temperature rise?
Answer and explanation
30 °C
The cooler object rose from 30°C to 60°C, a change of 60 − 30 = 30°C.