An airbag is a safety device in a car that is designed to inflate rapidly during a collision and cushion the impact of the driver or passenger with the interior of the car. The airbag itself is made of a thin, nylon fabric and is folded inside the steering wheel or dashboard of the car.

The airbag system contains several components, including an airbag module, which houses the airbag, and a crash sensor, which detects a collision and triggers the inflation of the airbag. The system also includes an inflator, which is a canister of gas that rapidly inflates the airbag when triggered by the crash sensor. The gas used in the inflator is usually sodium azide or ammonium nitrate, which produces a controlled explosion to rapidly inflate the airbag. However, newer airbag systems may use alternative inflators, such as compressed gas or small explosives.