The safety air bag system in an automobile uses chemical reactions in order to function. When a collision occurs, a sensor indicates that the car’s momentum has changed and this triggers a series of chemical reactions that quickly produces an appropriate amount of gas in order to inflate the safety air bag. The safety air bag, in turn, works to minimize the harm to the car’s driver and passenger(s) during a collision. In this activity, students will work to understand how the safety air bag system works, they will design their own safety air bag using a similar chemical reaction to mimic the operation of the safety air bag. An emphasis will be placed on quantitative chemical calculations, experimental results with a chemical reaction, and the role of the limiting reagent and percent yield in these reactions.