THERMODYNAMICS · IDEAL GASES
Thermodynamic Transformations and the First Law
Follow an ideal gas through a reversible isothermal, isobaric, isochoric or adiabatic transformation. Explore pressure, volume, temperature, work, heat, internal energy and entropy.
Physical Parameters
Simulation: Cylinder and Piston
The cylinder dimensions are to scale: width and height use the same metric scale. The gas is modeled as an ideal system in equilibrium.
First law: ΔU = Q − W. Work W is positive when the gas expands.
Synchronized Graphs
The first graph is a pressure–volume (p–V) state diagram; the others show evolution along the path. Select a point or enter an exact time.
p–V Diagram: Reversible Path
● Start ● End ● Selected State
Pressure vs. Time
Temperature vs. Time
First Law: Q, W, ΔU vs. Time
● W (work by gas) ● Q (heat to gas) ● ΔU (internal energy)
Entropy Change vs. Time
Data Table
Model Assumptions and Limitations
Ideal gas with constant heat capacities and amount of substance undergoing a quasi-static, reversible process.
Gas pressure and external pressure differ only infinitesimally along the path: this is not a rapid compression, shock wave or irreversible transformation.
Reversible heat exchange requires a thermal environment that follows the gas temperature. The animation time does not determine an actual heat flow rate.
No frictional losses, chemical reactions or phase changes.
THERMODYNAMICS EXPLAINED