A machine is a device that uses energy to perform a task or make work easier. Machines help us do things that would be difficult, slow, or impossible with our hands alone. A bicycle is a machine that turns the motion of your pedaling into faster movement. A washing machine cleans clothes by spinning and spraying water in ways your hands never could. Even simple tools like scissors and bottle openers are machines: they multiply your strength or change the direction of your force to help you cut or pry.

Machines can be wonderfully simple or incredibly complex. A lever, one of the oldest machines, just needs a rigid bar and a pivot point to lift heavy objects. A computer, by contrast, contains billions of tiny switches working together at lightning speed. Some machines like cars need fuel or electricity to run, while others like manual can openers work purely from the force you apply.

The word machine can also describe something that works with impressive efficiency or power. A basketball team that scores effortlessly might be called a scoring machine. When you practice a skill so much that you can do it almost automatically, you might become a machine at that particular task.

From the printing press to the steam engine to the smartphone, machines have transformed how humans live and work. Understanding machines means understanding how the world around you works.