### Demos for Thermal Physics Ralph Baierlein

Many items are merely models that aid the students in visualizing the mathematics. Those demos that are genuinely novel physical demonstrations are given in bold face.

1. Hot plate (which, when turned on, glows in the dark), glass beaker, and snow: to illustrate the idea of heating an object by conduction.

2. Heat lamp: ditto for heating by radiation

3. Glass cylinder with Styrofoam piston: for discussing expansion of a gas (and compression). (Used again later with Carnot and Otto cycles.)

4. Wooden "pincushions" for momentum arrows in thermal equilibrium (blue arrows for low temperature, red for high T).

5. Model: glass battery jar and beaker of marbles (for the context in section 2.6 of the text).

6. Glass cylinder with Styrofoam piston, heat lamp, and bricks: for discussing the Carnot and Otto cycles.

7. Model for cubical lattice in space (for density of single-particle states).

8. Show x, y, z axes for density of single-particle states.

9. Two-liter beaker with water, ice cubes in plastic bag (for section 4.3).

10. Disk of copper, model of "sample" (for context in section 5.2)

11. Electromagnet and compass needle (for review of magnetic moment, prior to section 5.3).

12. Rüchart's experiment (apparatus, stop watch, meter stick, masking tape, calculator). For idea of adiabatic compression and expansion and for homework problems 1.6 and 1.7 (chapter 1). Need to keep the tube vertical; otherwise there is too much sliding friction.

13. Thermoscope: Florence flask, partially filled with water (dyed black) and with glass tube. Heat with heat lamp. Example of how pressure varies with volume (as I insert the stopper) and with temperature.

14. Leslie cube and radiometer: show that radiant flux from hot surfaces (all at the same temperature) depends on the surface material: copper, stainless steel, flat black, and asbestos. Impressive!

15. Tungsten lamp and rheostat: changes in color as temperature changes (because power dissipation changes).

16. Model of solid with little cubes connected by springs.

17. Liquefy oxygen and then hang it between the pole faces of a magnet, thus demonstrating the paramagnetism of liquid oxygen.

18. Two tennis balls connected by a spring: model for a diatomic molecule.

19. Seebeck demo: heating one junction of a thermocouple produces a huge electric current; the ensuing magnetic field can hold a piece of metal, from which one can suspend an impressive weight (actually, a student). Offer qualitative explanation by using the chemical potential.

20. Model for scaling: two identical wooden blocks.

21. Demos of chemical reactions:

1. Silver nitrate (in solution) and sodium chloride (in solution).
2. Alcohol and air.

22. Model of constant temperature bath: flask with warm water and a stoppered test tube.

23. Models (via tennis balls) of homonuclear and heteronuclear diatomic molecules.

24. Critical point of carbon dioxide and critical opalescence. Do demo both in shadow projection and with video camera?

25. Compass needle on a pin; additional bar magnet. For discussing paramagnetism in chapter 14.

26. Fire syringe. Dramatically shows that the temperature rises when air is compressed adiabatically. Commercially available and cheap.

The above list was extracted from my notes for my Spring 1996 class. Section and chapter references refer to my book, Thermal Physics. For more information about any demo, send me e-mail.