Mechanical engineers design tools, engines, machines, and other mechanical equipment. They design and develop power-producing machines such as internal combustion engines, steam and gas turbines, and jet and rocket engines. They also design and develop power-using machines such as refrigeration and air-conditioning equipment, robots, machine tools, materials handling systems, and industrial production equipment. The work of mechanical engineers varies by industry and function. Specialties include, among others, applied mechanics, design, energy systems, pressure vessels and piping, and heating, refrigeration, and air-conditioning systems. Mechanical engineers also design tools needed by other engineers for their work. The American Society of Mechanical Engineers (ASME) lists 37 technical divisions.
Source: Landis, Raymond B. Studying Engineering; A Road Map to a Rewarding Career, Los Angeles: Discovery Press, 2007.