Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-L] Energy & Bonds



I'm not quite sure I understand the question. I certainly wouldn't use the
word "spring" in the context of a 1/r^2 force. I would and do use the word
"spring" in the context of modeling the interatomic interactions in a solid
that behaves in a spring-like manner at the macroscopic level (with some
discussion of the limitations of this model, since the actual potential
energy well isn't a parabola).

In our Matter & Interactions curriculum we make a big deal of the
ball-and-spring model of a solid. For us it comes up in three quite
different situations during the "mechanics" semester (in which we
deliberately integrate mechanics and thermal physics): stretching a wire
(macro-micro connections), speed of sound (a model of a line of atoms
connected by "springs" whose stiffness can be obtained from Young's modulus
shows a speed of propagation of a disturbance that agrees with the
experimental speed of sound), and finding the temperature dependence of the
specific heat for particular metals using the Einstein version of the
ball-and-spring model, again in agreement with experimental measurements).

This is an attempt to show that fundamental principles plus simple atomic
models of matter make it possible to understand and explain a wide range of
phenomena, in this case phenomena that appear on the surface to be
completely unrelated.

Here is the speed-of-sound calculation done at the micro level (choose
04-SpeedOfSound):

http://www.glowscript.org/#/user/GlowScriptDemos/folder/Examples/program/MatterAndInteractions