Mechanical engineering involves designing and producing both small and large parts from idea generation through market introduction. It requires broad skills and covers a wide range of topics from engineering and materials science to physics. The main purposes of mechanical engineering are to design, manufacture, and maintain mechanical systems, which includes areas like micro-electro-mechanical systems, friction stir welding, nanotechnology, mechatronics, composite materials, biomechanics, computational fluid dynamics, and acoustical engineering.