Adiabatic wall
= Adiabatic wall
An adiabatic wall prevents <heat transfer>. Two bodies at $300\,\mathrm K$ and $350\,\mathrm K$ can remain separated by a rigid adiabatic wall with no <heat transfer>, although they are not in <thermal equilibrium> with each other. An adiabatic boundary alone need not make a system an <isolated system>: a moving insulated piston can still transmit <work>. Isolation additionally excludes matter transfer and every <energy> exchange.