> If the helmet wasn't damaged in the crash it meant the energy was harmlessly transferred into your head.

Foam can and does distribute and absorb shock without being significantly damaged or destroyed in less severe collisions, crashes that can still put you in the hospital without a helmet.

I would maybe describe how helmets work as having a shock-absorbing cushion that slows deceleration of it’s contents. Talking about “energy” is bound to be misleading or confusing, since from a given speed, you always transfer the same amount of energy no matter how you stop, whether it’s a sudden strike against concrete or a slow gentle braking, or even waiting several minutes for air and tire friction to wear out all your kinetic energy.

I don’t want the helmet to be damaged or destroyed only because that means the crash is bad or severe.