How do zippers work?
For grown-ups: the science
A zipper slider pushes matching tiny teeth together or pulls them apart.
A zipper consists of two tapes with interlocking elements, often called teeth, and a slider. The slider's internal channels bring opposing elements together so they interlock, or guide them apart when moved in the other direction.
What about...?
Ask your child's own question
Transcript
Look at the zipper on your jacket. How can those tiny teeth join together so neatly?
A zipper has two rows of tiny teeth, one on each side. The teeth are shaped to fit together.
When you pull the slider up, it guides the teeth into a joined line. Each tooth hooks with the one across from it.
When you pull the slider down, its shape gently separates the teeth. Then the two sides can open again.
So a zipper works because its slider joins or separates its tiny, matching teeth.