Airbags

Airbags save lives in car crashes but there is science behind that is involved in order for the airbags to work properly. The science that is involved is called the law of motion. According to the article How Airbags Work states this about the law of motion in air bags " First, we know that moving objects have momentum (the product of the mass and the velocity of an object). Unless an outside force acts on an object, the object will continue to move at its present speed and direction. Cars consist of several objects, including the vehicle itself, loose objects in the car and, of course, passengers. If these objects are not restrained, they will continue moving at whatever speed the car is traveling at, even if the car is stopped by a collision.", explaining how the law of motion is used in order for the airbags to work. 
Another science that is involved in airbags is the gas laws. Some of the gas laws are Boyle's gas law , Charles's Law , and Avogadro's Law.  The gas law that is involved is Charles's Law because when the temperature of the nitrogen gas increase so does the volume thus inflating the airbag. The link above of the article How Airbags Work gives more information of how the airbags and how it is a safety device in car. Here is a link to a video that will show how an airbag will work in action. http://www.youtube.com/watch?v=d7iYZPp2zYY