Ask a class to draw a robot and most pupils will draw a metal person with a square head. Real robots rarely look like that. Today's robots include car-welding arms, floor-cleaning discs and a six-wheeled rover on Mars. This guide gives pupils a simple way to decide what counts as a robot, and to argue about the tricky cases, which is where the real learning happens.
Age range: roughly 8 to 14 (upper KS2 to KS3). Time: one 45 to 60 minute lesson, or two shorter sessions.
Curriculum links (National Curriculum in England):
- KS2 Computing:
design, write and debug programs that accomplish specific goals, including controlling or simulating physical systems
- KS3 Computing:
design, use and evaluate computational abstractions that model the state and behaviour of real-world problems and physical systems
- KS3 Design and technology:
apply computing and use electronics to embed intelligence in products that respond to inputs [for example, sensors] and control outputs [for example, actuators] using programmable components [for example, microcontrollers]
Suggested use: teach the sense, decide, act loop, run the sorting activity in pairs, then use the checklist as an exit ticket.
Quoted from the current programmes of study for computing and design and technology (2013). A revised curriculum is due to be taught from September 2028.
The simple answer: sense, decide, act
For the classroom, a good working definition is this: a robot is a machine that can sense what is around it, decide what to do using a computer program, and then act on the physical world, without a person controlling every move. Ingenia, the Royal Academy of Engineering's magazine, says much the same: a robot senses its environment, plans an action and carries it out.
Sensors collect information: cameras, bump switches, distance and light sensors.
A processor (a small computer) runs a program that turns the information into a choice: go, turn or stop.
Actuators carry out the choice: motors turn wheels, and arms lift and grip.
Take a robot vacuum. Its bumper senses a chair leg, its program decides "obstacle, so turn", and its wheel motors make the turn. Then the loop starts again.
Where does the word come from?
The word is younger than many pupils expect. It comes from the Czech word robota, meaning forced labour, and was made famous by Karel Čapek's 1920 play R.U.R., in which factory-made artificial workers eventually rebel. The idea of machines that move by themselves is far older: our interactive history of robotics timeline starts with ancient water-powered automata.
Not everyone draws the line in the same place
Britannica defines a robot as "any automatically operated machine that replaces human effort, though it may not resemble human beings in appearance or perform functions in a humanlike manner". BBC Bitesize's KS2 guide is broader still. It describes microwave ovens, washing machines, smoke alarms, lifts and automatic doors as simple robots, because they work automatically and are controlled by a computer program.
That disagreement is useful. Our three tests below are deliberately stricter, so pupils have to justify their answers. There is no single official definition to memorise; the skill is reasoning from evidence.
Robot or not? The three tests
| Test | Question to ask | Example that passes | Example that fails |
|---|---|---|---|
| Senses | Does it collect information about its surroundings? | A robot vacuum's bump and cliff sensors | A wind-up toy car |
| Decides | Does a program choose what to do, based on what it senses? | A Mars rover choosing a safe path around rocks | A remote-controlled car, where a person makes every choice |
| Acts | Does it move or change something in the physical world? | A factory arm welding car parts | An app that only shows information on a screen |
If a machine passes all three tests, call it a robot for this activity. If it passes only one or two, call it "automated" and discuss what it would need to become a robot.
What robots are good at, and what they still find hard
Robots tend to do well at jobs that are repetitive, dangerous or need great precision, especially in places that stay the same. They still struggle when the world is messy and full of surprises.
| Robots are good at… | Robots still find it hard to… |
|---|---|
| Repeating the same welding or lifting job all day in a factory | Tidy a messy bedroom full of objects they have never seen before |
| Exploring places that are dangerous or far away, such as Mars | Pick up soft, fragile or oddly shaped things reliably |
| Vacuuming a floor while nobody is at home | Cope with unexpected situations that need common sense |
Mars shows why the "decide" step matters. Because radio messages between Earth and Mars are delayed, NASA's drivers cannot steer the Perseverance rover with a joystick. Instead, its AutoNav system maps the ground ahead, spots hazards and plans a route around them, while the team on Earth chooses where it should go. For robots shaped like people, see our explainer on what humanoid robots can and can't do.
Classroom activity: robot or not?
Work in pairs. For each machine, decide whether it senses, decides and acts. Be ready to explain your answer to the class.
- A robot vacuum cleaner
- A remote-controlled toy car
- A washing machine
- A puffin crossing (the pedestrian lights with the red and green figures on your side of the road)
- An automatic sliding door
- A smoke alarm
- A wind-up toy
- A Mars rover
Discussion: which machine was hardest to sort, and why? What extra information would change your answer?
Notes for teachers: the vacuum and rover pass all three tests. The remote-controlled car acts, but a person decides. The wind-up toy cannot sense. The smoke alarm's only action is a sound: does that count? The puffin crossing makes a great debate, because GOV.UK says its signals can detect pedestrians, vary the crossing time and cancel the request if someone walks away.
Printable checklist
Print this as a handout or exit ticket (Ctrl+P, or Cmd+P on a Mac). Three ticks means it is a robot.
| Machine | Senses | Decides | Acts |
|---|---|---|---|
| Machine 1: ______________________ | ☐ | ☐ | ☐ |
| Machine 2: ______________________ | ☐ | ☐ | ☐ |
| Machine 3: ______________________ | ☐ | ☐ | ☐ |
| Machine 4: ______________________ | ☐ | ☐ | ☐ |
Challenge: explain in one sentence why one of your "not a robot" machines failed a test.
Key words
- Sensor: a part that collects information about the world, such as light, distance or touch.
- Processor: the small computer that runs the robot's program.
- Algorithm: a step-by-step set of rules for solving a problem.
- Actuator: the part that makes something move, such as a motor.
- Autonomous: able to carry out a task without a person controlling each step.
The big idea
Every robot, from a floor cleaner to a Mars rover, runs the same loop: sense, decide, act. Better parts make better robots, but the loop does not change. Understand it and you can make sense of almost any robot you meet.