Machines affect virtually every aspect of our lives. The clothes we wear, food we eat, and buildings that shelter us were all made with the aid of machines. Machines do important tasks in our homes — they provide warmth, wash clothes, and refrigerate food. We routinely climb aboard machines to transport us to and from work and school. Hospitals rely on machines to detect medical problems and to keep sick and injured patients healthy and alive. Machines even entertain us.

Machines enable us to do more things, do them faster, and do them with greater ease. But machines often break or wear out. When this happens, people realize how much they depend on them. Many people have careers dedicated to inventing, designing, building, repairing, and selling machines of all types.