system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what happens when a pair of shears hits that creamy smooth glide-cut and what causes this?
gpt
The first thing that you need to understand is that when you use scissors in the open close motion, you're not really "cutting". You're tearing the paper. You're just doing it really really.... really precisely.  Put a piece of paper on the edge of a desk. Hold it down with one hand and pull the part hanging off in a downward motion and you can see it "cut" along the edge of the desk. And this is the same process that scissors use.

Now the thing about the scissors themselves is that they're just two knives bolted or riveted together. So, when you find that sweet spot where the scissors glide through,  this is where the blade of the scissors is actually cutting. The paper is no longer being ripped between two edges, it's hitting one of the blades and slicing to either side of that blade. Just like if you took a sharp chefs knife and sliced through it.