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How does an airbag work?
Quick answer
An airbag works by detecting a crash in milliseconds and instantly inflating a cushion to stop your body from hitting the hard interior. A sensor triggers a rapid chemical reaction that fills the bag with gas faster than you can blink.
Step by step
- Crash sensors detect the sudden, severe deceleration of a collision.
- They trigger an igniter that sets off a fast chemical reaction inside the inflator.
- The reaction produces a burst of gas that inflates the bag in about 1/20th of a second.
- The bag cushions the head and chest, then deflates through vents to absorb the impact.
- Airbags are designed to supplement seatbelts, not replace them.
People also ask
How fast does an airbag inflate?
Extremely fast — in roughly 20 to 30 milliseconds, quicker than a blink, because it must deploy before your body moves forward in a crash.
Why do airbags need seatbelts too?
Airbags cushion you at the right position and moment; the seatbelt keeps you in that position. Without a belt, an inflating airbag can itself cause injury.
What inflates the airbag?
A sensor-triggered chemical reaction rapidly produces gas (often nitrogen) that fills the bag — not stored air, which couldn't deploy fast enough.
Part of the guide: Everyday Machines →