§7.2, §7.3, and §7.4 Density, Compressibility, Thermal expansivity: We will find that the density of solids reflects the type of bonding present; the compressibility tells us about the pair-potential between atoms; and thermal expansivity tells us about the asymmetry of the pair-potential .
§7.5 Speed of sound: Sound waves in solids are considerably more complex than in gases. However we relegate much of this complexity to Appendix A2 and focus on the trends in the data, allowing us to get a good feel for the factors involved.
§7.6 Heat capacity: The heat capacity of most solid elements at around room temperature can be understood using an exceptionally simple model of a solid. However, the temperature-dependence of the data, and the data which cannot be explained by this model, will lead us to a more realistic model, and a surprising connection to §7.5 on the speed of sound.
§7.7 Electrical properties: The difference in conductivity between metals and insulators is an amazing 20 orders of magnitude. Not surprisingly, we will use quite different models to understand the two categories of solids. More surprising is the simplicity of each of the models that we will use. For metals we will use the free electron model of a solid we discussed in §6.5, and for insulators we will ignore the bonding between the atoms almost entirely!
§7.8 Thermal conductivity: Although simple in principle, the data and the theory are surprisingly complex, and we attempt to understand only the temperature-dependence of the data.
§7.9 Optical properties: In Chapter 2 we said that the refractive index of a material is related to its dielectric constant. Using this result and Newtons laws of motion we will be able to explain the values, and the variation with wavelength, of the refractive index of transparent solids. Amazing.