AirBags
AirBagsAutomobiles are being equipped with airbags that inflate on collision to protect the driver or passenger from injury. A car’s airbag is located on the steering wheel, this airbag is for the driver, and on the dashboard, this airbag is for the passenger. Automobile airbags are inflated by the electrical system and sensors in the car that triggers a chemical reaction to occur. When a car is involved in a car accident the airbag rapidly inflates and deflates to cushion the driver or passenger. In addition, for an airbag to successfully inflate, the propellant goes through a chemical reaction to produce the gas that inflates the airbag.
An airbag is successfully inflated when the automobile’s electrical system and sensor detect that the automobile has been involved in an accident. This whole process is part of a complex electrical system that a car is equipped with. The sensors consist of a tube containing a ball held in place by a spring. In a frontal impact, the ball is forced against the spring in proportion to the severity of the crash. Other systems use an accelerometer instead of crash sensors, frequently located within the steering column or in the airbag assembly itself. An accelerometer is more sophisticated than the ball-in-tube crash sensor, and will likely see more widespread use in future models. Nearly all airbag designs are engineered to inflate when the sensors register a crash equivalent to hitting a solid barrier at 10-12 miles per hour. When a car is involved in an accident, and it loses velocity, and the impact is hard and fast enough, it triggers the airbag’s sensors. When the sensors detect that a high-impacted front-end collision has occurred it sends an electric current to a wire. This wire heats up, sending electricity into a heating element in the propellant, causing it to oxidize rapidly and the charge in the inflator of the airbag undergoes a chemical reaction, producing a gas that rapidly inflates the bag.
Airbags on the car’s steering wheel or the car’s dashboard, go through a rapid process so the airbag can inflate. The airbags are securely packed inside the steering wheel or on the dashboard ready to inflate when the car’s sensors detect a crash. To prevent or lessen any harsh injuries during a crash resulting from the driver or passenger’s face hitting the airbag, manufacturers use one of four different folding patterns, they are accordion, modified accordion, pleated accordion, and overlapped fold to pack the airbag into the steering wheel and dashboard. The folds are designed to decrease or eliminate the "slap" received by the driver or passenger as the airbag inflates. When the car gets into an accident sensors trigger the reaction and the airbag inflates in less than 1/20 of a second. The airbag itself is lubricated with different lubricants such as chalk or talcum powder, the manufactures use these lubricants so that the airbag can expand quickly and smoothly. After the inflation occurs, the airbag must automatically deflate, by venting the gases it built up inside the airbag. The bag must deflate in order for the driver or passenger to resist the impact and so they will not be wedged in between the wreck.
The science behind the inflation of an airbag is that the airbag is inflated when it successfully goes through a chemical reaction. The reaction occurs when the car’s sensors detect that a crash has occurred. The chemical reaction produces a gas that inflates the airbag, the gas that the chemical reaction produces is nitrogen gas. The reaction occurs when sodium azide ignited by a spark, reacts with iron (III) oxide, to produce the nitrogen gas that the airbag contains. The gas this chemical reaction produces is inert, it is not caustic, toxic, or explosive. As the gas expands, it cools considerably, as predicted by Charles' Law. As soon as the airbag inflates, it begins to deflate in order to cushion the driver or passenger during the accident. The airbag deflates 0.3 seconds after it is successfully inflated by this chemical reaction. The overall chemical reaction that occurs is when Sodium Azide reacts with Iron (III) Oxide to produce Sodium Oxide and Iron and Nitrogen Gas. This chemical reaction can be represented with the balanced chemical equation of: 6NaN3(s) + Fe2O3(s) 3Na2O(s) + 2Fe(s) + 9N2(g).
The purpose of automobile airbags is to protect a driver or passenger when they are involved in an automobile accident. The car’s electrical systems and sensors are the beginning of the process on how the airbag inflates. When the sensors have detected that an automobile has been in an accident it triggers the automobile’s airbags to rapidly inflate and deflate in order for the driver or passenger to be securely cushion during the impact. Chemical reactions occur when these sensors trigger the airbag to be inflated, sodium azide is the propellant used as a reactant to produce nitrogen gas, the gas that the airbag is inflated with. Consequently, the whole process of the inflation of automobile airbags is caused by sensors and a chemical reaction producing nitrogen gas to inflate the airbag.