A steering wheel is the circular control that drivers turn to change the direction of a car, truck, or other vehicle. When you turn the steering wheel to the left, the front wheels turn left and the vehicle follows. Turn it right, and the vehicle goes right.

The steering wheel connects to the front wheels through a system of gears and rods. Small movements of the wheel create larger movements in the wheels, giving the driver precise control. Race car drivers grip their steering wheels tightly through sharp turns, while someone parking might spin the wheel hand over hand to squeeze into a tight space.

Ships also have steering wheels, though on boats they're often called the helm or ship's wheel. These maritime steering wheels are usually much larger than car steering wheels and positioned vertically, and they control a rudder at the back of the ship rather than wheels.

Before steering wheels became common in the early 1900s, many cars were controlled by levers called tillers, which were harder to use. The steering wheel helped make vehicles easier and safer to control, turning cars from experimental contraptions into practical transportation.