Physics 112: Thermodynamics and Statistical Mechanics

Text: An Introduction to Thermal Physics by Daniel Schroeder

Chapter 4: Engines and Refrigerators

Stirling Engine
The Stirling engine is an example of a heat engine that converts heat into mechanical motion. It does this through cycling compression and expansion of gas in the two cylinders. One cylinder is heated with a flame and the other is cooled by a heat sink. The cool cylinder will contract as heat is transferred to the heat sink and the air will fill the heated cylinder. The gas will expand and will once again fill the cool cylinder.

Hero’s Engine
This is another demonstration of how to convert thermal energy into mechanical energy. A special glass container filled with water is placed over a Bunsen burner. Two glass tubes coming out of the sides of the container direct the steam coming out of the container to spin the container on its axis.

Heat Engine/Gas Law Apparatus
A near frictionless piston can be moved up and down by changing the temperature of the air inside. The piston can also lift a small mass, which shows how thermal energy can be transformed into usable work.

Chapter 5: Free Energy and Chemical Thermodynamics

Triple Point of Water
This demonstration shows the triple point of water using a small vacuum chamber and a small dish of cold water. Requires 10-15 minute prep prior to demonstration and presence of current Demo Room manager or other qualified staff member.

Curie Point
This demonstration shows that at its Curie temperature (achieved by using a blowtorch), a chunk of iron will lose its magnetic properties. Conversely, as it cools it will re-magnetize.

Additional Demos

Four vanes (one side white, one black) suspended on a pin. When light is shined, the apparatus turns in the direction of the white sides of the vanes.

Beam of Cold
This demonstration shows the second law of thermodynamics: the heat flow statement.

Leidenfrost Effect
Droplets of water hovering on top of brass plates, floating on a cushion of water vapor.