The windows in your car are more than just something that you can look out of. They are an important part of your car's overall structural integrity. For example, the front and back windshields help to tie your car's frame together so that it is one solid whole. The way that the glass in your windshields and windows are made is a safety feature as well. They aren't the same kind of glass, though. 

Laminated Glass

The glass in your front windshield is made up of laminated glass. Laminated glass is made up of two layers of glass that are stuck together with a powerful, clear adhesive and then pressed together until they become one whole piece of glass. The laminated glass is stronger than any one piece of glass would be on its own. That means that it can stand up to things like pebbles or rocks that get thrown up from the road without necessarily breaking all the way. The lamination also helps the glass stay in one piece if it is broken in an accident. Instead of shattering, it will break but will still be all in one piece because the lamination will keep all the pieces of glass together. That means it won't shatter on you and hurt you. 

Tempered Glass

Generally, all the other windows of your car are made out of tempered glass. Like laminated glass, tempered glass is stronger than regular window glass. It needs to be so that you stay in the car in the case of an accident. Tempered glass is made by taking glass and then rapidly heating it and cooling it back down. That does something called creating equilibrium in the glass. That equilibrium means that if the glass breaks, it isn't going to shatter into pieces that could hurt you. Instead, it will break into cubes, which usually don't hurt you if you were to have them on you. Glass bakingware is also made up of tempered glass and if you have ever broken it, you will see the same kind of effect. 

The fact that your car's windows need to have specific kinds of glass for your safety means that you can't just go anywhere and have it replaced. You have to make sure that you get the job done by someone who specializes in auto glass repair. You don't want to do anything that could jeopardize your safety.