The Big Bang Theory2007

Sheldon:
Do you want to hear an interesting thing about stairs?

Leonard:
Not really.

Sheldon:
[going on anyway] If the height of a single step is off by as little as two millimeters, most people will trip.

Leonard:
I don't care. [thinks about it] Two milli - that doesn't seem right.

Sheldon:
It's true - I did a series of experiments when I was twelve. My father broke his clavicle.

Leonard:
Is that why they sent you to boarding school?

Sheldon:
No - that was the result of my work with lasers.