An air pump is a device used to inflate or deflate objects by moving air in or out of them. There are many different types of air pumps, ranging from manual hand pumps to electrically powered pumps, and they are used for a variety of purposes. John had trouble blowing up many balloons without a balloon pump and experienced pain. He solved this problem by using an empty plastic bottle with a rectangular-shaped hole in the cap, a cut piece of balloon stretched over it, and a small hole in the bottle. By pressing and releasing the bottle, he created an air pump to inflate the balloons without any discomfort.
Air pumps utilize fluid mechanics and thermodynamics principles to increase air pressure inside an object being inflated, such as a bicycle tire. The ideal gas law is used to calculate the pressure inside the tire. As air pressure increases, the object becomes more rigid and can support more weight. The efficiency of the pump is determined by how much of the work done is converted into useful work, such as inflating the tire, and how much is lost as heat. Understanding these principles is important to effectively use and optimize the use of air pumps.