Instruction:
How does a zipper work?

Response:
A zipper is used to repeatedly open and close two edges of a surface together, typically on garment bags, luggage, coats, and pants. Zippers refer to the system of two surface edges and a slider, where a human pulls the slider one direction to open and another direction to close. The slider interlocks "teeth" together to make the surfaces bind when they close, and disconnects the teeth apart when then open. Zippers are usually made from metal or plastic.