The first modern robots were made by an American scientist and inventor named William Grey Walter. Since then robots have robots have come a long way and they have numerous, practical uses. A robot is defined as a machine that senses things around it and moves by itself. Robots have been used on car assembly lines. They have also been used to lift extremely hot or cold objects, to lift heavy objects, to clean up messes, to perform tasks in space, and to perform military tasks. A humanoid (a human-like) robot in Japan named Saya has even worked as a school teacher and receptionist. With the advancements in technology the possibilities of tasks robots can perform seem endless.