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Adiabatic Piston Compression (2D)

Drive a piston into a sealed gas cylinder and watch pressure and temperature follow PV^γ = constant, a steeper curve than the isothermal PV = constant line on the same P-V diagram, as compressing the gas heats it with zero heat added or removed.

Physics & Mechanics2DModerate60 FPS⇄ 3D version

Drive a piston into a sealed gas cylinder and watch pressure and temperature follow PV^γ = constant, steeper than the isothermal PV = constant line on the same P-V diagram, as compressing the gas heats it with zero heat added or removed.

⚙ Under the hood

An adiabatic process exchanges no heat with its surroundings (Q = 0), so all of the work done compressing the gas goes straight into its internal energy. Combining the first law with the ideal gas law gives P·V^γ = constant, where γ = Cp/Cv is the heat-capacity ratio — 1.4 for a diatomic gas like air, 5/3 ≈ 1.667 for a monatomic noble gas. Because γ > 1, the adiabatic curve is always steeper on a P-V diagram than the isothermal PV = constant hyperbola through the same starting point — the simulation draws both so the difference is visible directly. The same relation gives the temperature: T = T₁·(V₁/V)^(γ-1), the counter-intuitive result that squeezing a gas fast enough to prevent heat escaping makes it hotter, exactly what happens inside a diesel engine's cylinder and to a rising, expanding — and therefore cooling — parcel of air.

adiabaticthermodynamicsPV diagramgas lawsheat capacity ratiodiesel engine

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install