Complex Machines
Elementary School
Definition
Machines made by combining two or more simple machines to perform work. A bicycle, for example, combines wheels and axles, levers, and gears. Complex machines let people accomplish tasks that would be difficult with a single simple machine.
Worked examples
A bicycle combines wheels and axles (the wheels spin on axles), levers (the brakes), and gears (the chain and sprockets).
Multiple simple machines work together to let you steer, pedal, shift speed, and stop.
Scissors combine two levers (the handles) joined at a fulcrum, with two wedges (the blades) that cut.
The lever arms multiply your force while the wedges slice through material.
Common mistakes
- A complex machine must have motors or electricity → A complex machine only needs two or more simple machines working together Many complex machines like scissors, bicycles, and manual can openers have no power source at all.
- A wheelbarrow is a complex machine because it looks complicated → A wheelbarrow is a simple machine (a lever with a wheel and axle) Count the types of simple machines present, not how big or useful the tool is.
- Complex machines are always better than simple machines → Complex machines are better for certain tasks; simple machines are easier and sufficient for others Sometimes a single lever or ramp is the most efficient tool for the job.
Where you'll use it next
You'll study mechanical advantage in complex machines when learning about efficiency and energy transfer, and explore engineering design when analyzing how machines like cars, cranes, and robots combine simple machines to solve real-world problems.
See also
Reviewed by Pat Cheng, M.Ed. — StudyPug Curriculum Lead · Last updated June 6, 2026