Air-Bags

What are they?

Air-Bags are one of the common safety measures of a car and are now included in almost all new vehicles. They are actually sort of strong balloons which are folded into a car’s steering wheel and dashboard or more recently in the roof and doors too. They are supposed to bang open in case of an accident. They are able to blow up really fast.

The Theory Behind This Invention:

According to Sir Isaac Newton’s first law of motion, a moving object keeps on moving until there is some force acting on it to stop. Same goes for the forces and objects of a car. When a car crashes, it comes to a sudden stop. Every object that is attached to the car also comes to a stop. But wheat about the most important ones, the passengers. They are not actually a part of the car so they would just keep on going until they crash really hard onto the dashboard. At very high speed crashes, the driver and passenger may even crash into the windscreen, breaking it, and land meters ahead the car’s front! This will cause a violent injury which is the only thing we don’t want. Therefore we needed to come up with some way of stopping the passengers too without hurting them. So an American John W. Hetrick of Pennsylvania invented the air-bag which he called ‘the safety cushion’. The idea was to crash the passenger into the soft air-bag instead of the dashboard or anything other.

How Air-Bags work?

When a car crashes with something solid, it starts to decelerate or simply lose speed at a very high rate. An accelerometer sensor detects it and send a signal to the car’s computer (The deceleration of a crash is times faster than that of braking so the two can be easily distinguished). The computer then sends a signal to activate the air-bag circuit. Then, a heating element is triggered similar to the ones used in irons and toasters. This burns an explosive chemical in a chamber. Different systems use different chemicals. As the element burns, it releases lots of harmless gases like nitrogen or argon. This gas fills in the air-bag and it bursts open. Now, as we don’t want the bag to just keep getting bigger and itself suffocate the passengers to death, there are tiny holes in the bag which let air out as the passenger crashes into them. By the time the car stops, the bag will have been fully deflated.

Advantages of an Air-Bag:

Air-Bags are considered Supplementary Restraint System (SRS). They are supposed to be used along with seat-belts. Relying on Air-Bags without putting on your seat-belt can be very dangerous. Used along with seat-belts they do save lives. They prevent your head from crashing into the dashboard or steering. The seat-belt alone only stops your body from crashing but leaves your head unprotected which is perhaps the most important. Air-Bags are intended to protect your head and face.