Mystery Solved: Why Stepping on a LEGO Hurts so Darn Much

It doesn't matter how old you are or where you're from: If you're a human being then you know the horror of stepping on a LEGO. It's the ultimate relatable pain. You know if feels like a spiked wedge being shoved into your soft flesh. It feels like soldiers armed with bayonets entering your body through your heel. And somebody finally figured out why.


The answer involves three parts. The first part is easy to explain.

Basically, the bottom of your foot is one of the most sensitive parts of your body. It's up there with the tips of your fingers, your lips, and your, ahem, private areas.

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That means that there a lot of nerves concentrated in one spot, so you feel everything more. More tickling, more massaging, more LEGO-related pain.

(Interestingly, your butt is the least sensitive part of your body. So you'd be better off falling backwards onto a pile of LEGOs than stepping on one, but that's an argument for another day.)

The second factor is that LEGOs are hard. Not even considering the studs or the sharp corners (because, ow, those even hurt to talk about), a LEGO can withstand almost 1,000 pounds of weight before buckling.

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The third part involves a lot of math. This is what that looks like: 

A standard 2×2 Lego brick has a surface area of roughly 2.25 centimetres squared ... Let’s say a person weighing 75 kilos (165 pounds or 734 Newtons) steps onto it.

Now, the pressure on a given object is equal to the force applied divided by the area over which it is spread (P=F/A).  So even if that 75 kilo person were just standing on the Lego with one foot, rather than having their foot accelerating downward at some rate as with walking, this gives us 734 N/0.000225 m2 = roughly 3,262,222 pascals of pressure!

Basically, you're getting the force of your entire body weight plus your momentum shoved into one of the most sensitive areas of your body via a sharp and nearly unbreakable amount of plastic. So yeah, it hurts. It hurts a lot.

When was the last time you remember stepping on a LEGO?


Image via FamVeld/shutterstock

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