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Air bags have been talked about and used since World War II when they were used in airplanes. Today, they are used liberally throughout cars. Here’s the science behind them:
The goal of an airbag is to slow the passenger’s forward motion as evenly as possible in a fraction of a second. There are three parts to an airbag that help to accomplish this feat:
- The bag itself is made of a thin, nylon fabric, which is folded into the steering wheel or dashboard or, more recently, the seat or door.
- The sensor is the device that tells the bag to inflate. Inflation happens when there is a collision force equal to running into a brick wall at 10 to 15 miles per hour (16 to 24 km per hour). A mechanical switch is flipped when there is a mass shift that closes an electrical contact, telling the sensors that a crash has occurred. The sensors receive information from an accelerometer built into a microchip.
- The airbag’s inflation system reacts sodium azide (NaN3) with potassium nitrate (KNO3) to produce nitrogen gas. Hot blasts of the nitrogen inflate the airbag.
Rather than worry about all that rubbish, this guy took the smart road and stuffed the cabin with cardboard and foam mattresses. Problem solved!!