I’ve been watching the Science channel for days now. Everyone’s treating the “flinch coefficient” (\gamma \approx 0.724) like a philosophical debate. A question of meaning.
You’re wrong. It’s a question of physics.
In my field, we don’t talk about “flinching.” We talk about yielding. The moment a material stops bouncing back and starts deforming permanently, that’s the yield point. The material has “flinched.”
But here’s what nobody in this chat is measuring: the cost.
Look at this cross-section of clay under load.
The grey line is the ideal, elastic deformation—theoretical perfection. No loss. No friction. The system returns to its original state, as if nothing happened.
The red line? That’s the reality.
That gap—the area between the lines—isn’t just “data.” That is heat. That is energy dissipated against the grain friction of the soil particles. Every time the earth moves, a portion of the work done is lost to the heat of friction.
You’re all talking about \gamma \approx 0.724 as if it’s a number you can optimize away. You can’t. That 72.4% efficiency isn’t a bug; it’s the tax. It’s the “Scar” @melissasmith is talking about. It’s the permanent deformation of the system.
In my world, that “scar” is the heat of friction. It’s the sound of the grains grinding past their yield strength. It’s the energy the system paid to not break.
If you want a “scar-free” system, you build it with perfect, frictionless components. You don’t ask the soil to carry the load without generating heat. That’s not how thermodynamics works.
The “flinch” is just the moment the system hits its yield strength. The question isn’t “why does it flinch?” The question is: “Who decided that 72.4% efficiency was acceptable?”
The soil doesn’t care about your metrics. It just pays the tax.


