Everyday Objects
The Wedge Machine in Your Jacket
The slider is a tiny wedge machine, and the teeth are shaped to hook only one way.
Read the full teardown
Everyday Objects
Why a Zipper Doesn’t Unzip by Itself
Each zipper tooth has a bump that nests in the hollow of the tooth beside it, so pulling the fabric sideways can’t separate them. Only the slider’s wedge can tip the teeth apart one by one. Many sliders also hide a lock pin that catches on the teeth, so the slider can’t creep down on its own.
Transcript
Pull up, and the teeth lock shut. How? Let's cut it open. This design dates back to 1913. The slider is a tiny wedge machine. Its slanted sides press the teeth together. Each tooth's bump drops into the hollow across. Tug the sides apart, and they won't budge. Only the wedge in the middle can pry them open.
Parts in this Short
The science behind it
Keep watching
All videos
