An airbag is a safety device in cars that inflates instantly during a crash to cushion people from injury. Hidden inside the steering wheel, dashboard, or door panels, airbags stay flat and invisible until sensors detect a sudden, violent impact. Then, in a split second (faster than you can blink), they fill with gas and balloon outward to create a soft barrier between passengers and the hard surfaces of the car.

The technology works like this: crash sensors trigger a chemical reaction that produces a large volume of gas almost instantaneously, inflating the bag to full size in about 1/20 of a second. The bag then deflates quickly so it doesn't trap people inside the vehicle.

Airbags became standard equipment in cars during the 1990s and have saved tens of thousands of lives since then. They work best alongside seatbelts: the seatbelt holds you in place while the airbag provides extra cushioning. Modern cars often have multiple airbags positioned throughout the interior, including side airbags that protect during side-impact collisions.