After very long time, the temperature of the juice and the surrounding air
become the same. No
heat transfer occurs between them and we say they are in thermal equilibrium.
room temperature = 25.0 0C
When the temperature of the juice is less than the temperature of the surrounding air,
heat flows from the surrounding air to the juice. The juice and the
surrounding air are not in thermal equilibrium.
juice temperature = 3.00C
Heat from the surrounding air
time = 0 min
Heat from the tea
After very long time, the temperature of the tea and the surrounding air
become the same. No
heat transfer occurs between them and we say they are in thermal equilibrium.
room temperature = 25.0 0C
When the temperature of the tea is higher than the temperature of the
surrounding air, heat flows from the tea to the surrounding air. The tea and
the surrounding air are not in thermal equilibrium.
tea temperature = 90.00C
time = 0 min
When two objects are in thermal contact and they have different
temperatures, energy in the form of heat will transfer from the object with
higher temperature to the object with lower temperature. Transfer of heat
will continue until the two objects have the same temperature. When the two
objects have the same temperature there will be no heat transfer between
them and we say that the two objects are in thermal equilibrium.
Two objects are in thermal contact if heat can flow between them. This
can be done by making the two objects physically contact each other as when
you put a cube of ice in a glass of warm water. Thermal contact can also be
achieved without any physically contact as when you bring your hands near a
fire, you feel the heat of the fire even though there is no physical contact
between your hand and the fire.
