Isothermal vs. Adiabatic Compression

Theory

In an isothermal process the thermostat removes heat, so $T$ stays constant and $PV=$ const. In an adiabatic process no heat is exchanged: the work done by the piston raises the internal energy, so $T$ rises and $P{V}^{\gamma }=$ const (in 2D, $\gamma =2$). This is how a diesel engine ignites fuel without a spark.

What to observe

• Both boxes start identical at 300 K.

Try this

• Select each box and move the piston (volume) to 0.4: compare the final temperatures.
• Expand the adiabatic gas again: it cools down.

Also available in: Compressão isotérmica × adiabática (Português) · Compresión isotérmica vs. adiabática (Español)