So I'm trying to understand how the modulus works in metals. I understand that when the temperature rises, that means that the modulus decreases. But I do not understand exactly what it is or how it affects the way that the molecules would vibrate for instance, as kinetic sound energy moved through them. I get that it has to do with elasticity, but is it saying that the elasticity also goes down? The molecules aren't capable of moving as far from equilibrium? And if that's so, why are heated metals more likely to bend? Or is that a density-based issue and not a modulus issue?