How zipper works?

For a short history about the zipper; the earliest recorded zip-like fastener was patented by Elias Howe in 1851. The mechanism of the Howe's zip is similar to the ones we use today except that it did not contain any slider instead used a string that can be pulled to close the clasps. Then zipper was then renamed and patented by Whitcomb L. Judson with the name "clasp locker." But the series of attempts to improve and redesign the zipper was ended by the invention of Gideon Sundbäck in 1914 which resembles the modern zippers we have now. It has been coined with several names and one of them is the "C-Curity Fastener" and used mostly in workwear uniforms.

Zipper, just like how the early inventors thought about it, works in a principle of hook clasping in which a hook clasps with an eye. Before, it can be done with a string but these days a protruding latch called a slider is the one that locks or unlocks the series of hooks and eyes. In a cross section of the slider you will see the "Y" rail where in the two sides of the zipper pass. The sides of the zipper break and join at the point where the upper part of the "Y" and its leg meet.

For other info, Wikepedia listed types of zipper namely:

a. Coil zippers now form the bulk of sales of zippers worldwide. The slider runs on two coils on each side; the "teeth" are the coils. Two basic types of coils are used: one with coils in spiral form, usually with a cord running inside the coils; the other with coils in ladder form, also called the Ruhrmann type. This second type is now used only in a few parts of the world, mainly in South Asia. Coil zippers are made of polyester coil and are thus also known as polyester zippers. Nylon was formerly used and though only polyester is used now, the type is still known as a nylon zipper.

b. Invisible zippers' teeth are behind the tape. The tape's color matches the garment's, as does the slider, so that, except the slider, the zipper is "invisible". This kind of a zipper is common in skirts and dresses. Invisible zippers are usually coil zippers. They are also seeing increased use by the military and emergency services due to the fact that the appearance of a button down shirt can be maintained, while having a quick and easy system.

c. Metallic zippers are the classic zipper type, found mostly in jeans today. The teeth are not a coil, but are individual pieces of metal moulded into shape and set on the zipper tape at regular intervals. Metal zippers are made in brass, aluminium and nickel, according to the metal used for teeth making. All these zippers are basically made from flat wire. A special type of metal zipper is made from pre-formed wire, usually brass but sometimes other metals too. Only a few companies in the world have the technology. This type of pre-formed metal zippers is mainly used in high grade jeanswear, workwear uniforms, etc., where high strength is required and zippers need to withstand tough washing.

d. Plastic-molded zippers are identical to metallic zippers, except that the teeth are plastic instead of metal. Metal zippers can be painted to match the surrounding fabric; plastic zippers can be made in any color of plastic. Plastic zippers mostly use polyacetal resin though other resins are used as well, such as polyethylene.
e. Open-ended zippers use a "box and pin" mechanism to lock the two sides of the zipper into place, often in jackets. Open-ended zippers can be of any of the above specified types.

f. Closed-ended zippers are closed at both ends; they are often used in baggage.