The Strength Of A Single LEGO Brick
Why does stepping on a LEGO hurt so badly? First, the bottom of your foot is a sensitive area with many nerve endings to communicate pain. Second, the bricks are designed to be extremely hard, meaning they will withstand the pressure of your weight. And because the bricks are small, they hurt even more—pressure is equal to the amount of force divided by the area to which that force is applied.
Key Facts In This Video
The standard unit for pressure is the pascal, which is Newtons per meter squared. (0:20)
Because your weight is concentrated over a much smaller area when you step on a LEGO brick than when you step on the ground, it hurts very much. (1:51)
It's possible to lay on a bed of nails because your body weight is spread out over the nails, and the pressure is distributed. (2:28)