Advanced Topic 377 of 1102 Thermodynamics & Energetics
Adiabatic Process
A change with no heat exchange with surroundings.
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In-depth explanation of Adiabatic Process
An adiabatic process is one in which no heat is exchanged between the system and its surroundings, so q equals zero and the change in internal energy equals the work done. This happens when the system is well insulated or when a process is so rapid that heat has no time to flow. When a gas expands adiabatically it does work at the expense of its internal energy and therefore cools, while adiabatic compression warms it. For a reversible adiabatic process of an ideal gas, T times V to the power gamma minus 1 is constant, where gamma is the heat capacity ratio. Adiabatic behavior underlies the operation of diesel engines and the temperature changes seen in rising air masses.
Going deeper: Adiabatic Process
Key ideas: With q equal to zero, delta U equals w, and for an ideal gas delta U equals n Cv delta T. For a reversible adiabatic change, T V to the power gamma minus 1 is constant and P V to the power gamma is constant. Expansion cools and compression heats.
Common mistakes and connections: It is not the same as isothermal, since the temperature changes. Adiabatic curves on a PV diagram are steeper than isotherms. Applications include diesel ignition, cloud formation in rising air, and the two adiabatic steps of the Carnot cycle.
Visualization of Adiabatic Process
With no heat exchanged, the gas cools as it expands, so pressure falls faster on the adiabat (PV^1.4 constant) than on the isotherm. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Air compressed rapidly in a bicycle pump warms noticeably because little heat escapes during the fast compression.
Frequently asked questions about Adiabatic Process
What is Adiabatic Process?
A change with no heat exchange with surroundings.
Is Adiabatic Process a beginner, intermediate or advanced topic?
Adiabatic Process is a advanced topic in Thermodynamics & Energetics. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Adiabatic Process?
Study these earlier topics in Thermodynamics & Energetics first: Reversible Process, Irreversible Process, Isothermal Process.
What comes after Adiabatic Process?
The next topics in Thermodynamics & Energetics are Isobaric Process and Isochoric Process.
Can I practise Adiabatic Process with quizzes?
Yes. The interactive lesson includes a self-check question on Adiabatic Process, and the Thermodynamics & Energetics quiz draws on every topic in this area.
Where Adiabatic Process fits in Thermodynamics & Energetics
Adiabatic Process is topic 49 of 91 in Thermodynamics & Energetics.