You are probably quite familiar with things physicists and engineers call "Heat Engines": the petrol and diesel engines for cars and trucks are heat engines as they convert heat energy to mechanical work by exploiting the temperature gradient between a hot "source" and a cold "sink". The diagram below left shows this process schematically. Heat is transferred from the source (Thot) through the "" of the engine, to the sink (Tcold) , and in this process some of the heat is converted into work (W) by exploiting the properties of a working substance (usually a gas or liquid). Even a "Dunking Bird" is a heat engine (centre). This suggests a good EEI based on an experiment often done in thermodynamics labs in 1st year university physics or engineering. The diagram to the right shows the setup. It consists of a flask connected to a glass syringe (see description in the "Heating up Gases" suggestion above.


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