An adiabatic process is a thermodynamic change that occurs without any heat exchange between a system and its surroundings. In such a process, all the energy transfer is in the form of work, not heat. This means the system is perfectly insulated, or the process happens so quickly that there’s no time for heat to enter or leave.
In an adiabatic expansion, a gas does work on its surroundings and cools down, since its internal energy decreases. In an adiabatic compression, work is done on the gas, causing it to heat up as its internal energy increases.
Adiabatic processes are important in:
- Atmospheric science (rising air expands and cools adiabatically, leading to cloud formation),
- Internal combustion engines (compression and expansion strokes are nearly adiabatic),
- Refrigeration cycles (adiabatic steps help in energy transfer without heat loss).
They are governed by the first law of thermodynamics, where any change in internal energy is equal to the work done, since no heat is transferred. Understanding adiabatic behavior is crucial for modeling real-world thermodynamic systems.