A robot is a machine. It can sense what is around it. It can decide what to do. Then it does it. A robot has sensors to find out about the world. It has a computer to decide. It has motors, called actuators, to move. Sensors can be cameras and touch sensors. The computer uses what they tell it. Then it decides what to do next. After that, it drives the motors.

A robot vacuum cleaner drives itself around a home. It cleans the floor. Its sensors help it avoid bumping into things. They also help it avoid falling down stairs. Some robot vacuums build a map of the home. That way they can clean every spot. A robot vacuum can go back to its charging station by itself.

The first factory robot arm went to work in 1961. It worked at a car plant in New Jersey. The arm was named Unimate. Its job was moving finished metal castings. That was a dirty and dangerous job. People no longer had to do it. Robot arms in car factories do jobs such as welding, painting and putting parts on cars. In 2025, about 5 million industrial robots were working in factories around the world.

Robots often do jobs that are dangerous, hard or boring for people. They do jobs that people would rather leave to machines. That keeps people out of danger. In robotic surgery, a doctor sits at a console. The doctor moves robot arms that hold tiny tools. Robotic surgery does not replace the surgeon. The surgeon controls the robot arm.

Robot rovers with wheels drive around on Mars to explore it. A Mars rover drives to different spots. It uses a robot arm to hold tools up to rocks it wants to study. A small robot helicopter named Ingenuity flew on Mars too. It flew on April 19, 2021. It was the first aircraft to make a powered, controlled flight on another planet.

Many factory robots are programmed to do the same action again and again. They do it the same way each time. Some jobs are easy for people but hard to program into a robot. Moving around is one. Seeing and grasping things are others. A robot that walks on legs can fall over. A hard enough push can topple it.

The word robot comes from a play that was written long ago. The play is called R.U.R. It stands for Rossum's Universal Robots. In the play, an inventor makes human-like machines. They take over human work. The play is a critique of machines that dehumanize people. The Czech word robota means forced work.

Words to know

• sensors: parts that sense
• actuators: motors that move
• castings: finished metal pieces
• rover: wheeled robot
• critique: a close look

The short version

A robot is a machine that can sense what is around it, decide what to do, and then do it. It has sensors to find out about the world, a computer to decide, and motors called actuators to move. Robots often do jobs that are dangerous, hard or boring for people.

Quick facts

• A robot is a machine that can sense what is around it, decide what to do, and then do it.
• A robot has sensors to find out about the world, a computer to decide, and motors called actuators to move.
• The first factory robot arm went to work in 1961 at a General Motors car plant in New Jersey.
• About 5 million industrial robots were working in factories around the world in 2025.
• The word robot comes from a play called R.U.R., and the Czech word robota means forced work.