LEGO is fun--until you step on one barefoot. It's a deeply painful experience felt by anyone who has been a parent. Your kids' LEGO will try to kill you one day. Why are they so painful? Sonali Kohli of Quartz explains:
The sharp corners also exacerbate the pain, New York University physics professor Tycho Sleator tells Quartz via email. Pressure is equal to the amount of force divided by the area to which that force is applied, he explains. “When you step on something with a sharp corner, the force from the corner is concentrated over a very small region of your foot. This would result in a very high pressure on that small region of your foot.”
That also means that Lego encounters probably hurt you more than they do your lighter-weight kid, because the surface of the Lego matches the amount of pressure bearing down on it. When walking, that isn’t just the pressure of gravity: Movement multiplies your standing weight. For example, you might be exerting pressure of up to twice your body weight with each step just by walking, and running produces pressure of up to nine times your weight.
-via Jeremy Barker