Why is paper stronger (resists tearing) more at the perforation than elsewhere?

I never noticed that. It probably has something to do with the place on the cheque you’re holding on to. That matters a lot. Also, the embroidery (my cheques have that) with metal also weakens the paper.

Here’s a little experiment, have two people hold one cookie at each side with one of their hands. Then, challenge them to break off a bigger piece using only their one hand. You will notice the person with the bigger piece actually used less force than the other person to break the cookie!
Anyway, I think that example was used to explain that the more force you use under your fingertips (holding on to your cheque) vs. the lesser force (perforations), the more likely the cheque will crumble under your fingers.

< < Ugh. Is incredibly disappointed in his own grammar. ”...stronger more…” Sheesh!

I’m upset now, I wish I had a checkbook to tear. :-(

Clearly a Communist plot.

Oh. Crap. All this time, I thought it had to do with 9/11 and the otherwise inexplicable collapse of the WTC buildings.

A long time ago I read a science fiction story where some guy decided to research that very point. He realized that the only difference there was at the perforated lines was that there was more…nothing. So he realized that Nothing was stronger than paper.

Eventually he was building indestructible walls out of Nothing, using it as bullet-proof armor, etc. At one point someone showed up to assassinate him. “You might as well give up,” the guy said, “this desk is surrounded by pure Nothing.”

I can’t remember the author or the title of the story, but that has stuck in my mind ever since. And I think of it every time I rip a piece of paper and it doesn’t tear along the perforation.

At the perforation the paper is a tad bit more compressed (from the forced incision of the needle that makes the perforation) and thus a tiny bit stronger. The difference is not (should not be) noticeable to human dexterity.