Mechanical engineers research, design, develop, build, and test mechanical and thermal sensors and devices, including tools, engines, and machines.caused by, resulting from, or relating to a process that involves a purely physical as opposed to a chemical or biological change or process. mechanical erosion of rock. mechanically.Mechanical engineering skills are a mix of hard and soft skills covering areas such as math, computer skills, design and communication. Mechanical engineering offers one of the more expansive engineering disciplines because they work in many areas, including the manufacturing, research and automotive industries.