Mechanical engineers are curious about how things are made and work; they have a desire to solve problems and a talent for understanding the operation of mechanical devices. Mechanical engineering, the second largest engineering discipline and one of the oldest, applies the principles of mechanics and energy to the design of machines and devices.  Mechanical engineers work in all areas of manufacturing industries. They can work in research and development, management, maintenance, and production operations.  Some engineers become consultants in the research, design, and testing of technologies. Creativity combined with mechanical engineering skills is a great start for an inventor.