football helmets have a hard outer shell lined with a thick layer of plastic foam inside the shell. what is the primary purpose of the foam lining?

The foam lining in a football helmet is primarily there to absorb and reduce impact forces so less force is transmitted to the player’s head and brain.

Inside the hard outer shell, the foam acts like a cushion that:

• Compresses during a hit to soak up energy.

• Spreads the impact over a larger area and longer time, lowering the peak force on the skull.

• Helps reduce the risk and severity of head injuries such as concussions, compared with a hard shell alone.