Interactive mechanism · source-grounded teaching model
A river becomes a power source
Examine a current-driven wheel and its axle. The rotating paddles demonstrate how moving water can turn a mechanism, before gears or belts carry that power to other work.
Paddles. In a current wheel, flowing water acts on blades near the bottom. This differs from feeding water over the top of an overshot wheel.
Current, paddles and a turning axle
Different wheels, different water supplies
A current or undershot wheel receives water near its lower blades. An overshot wheel receives water from above, making use of its fall. The Science Museum Group’s timber models illustrate how wheel and bucket design affect filling, emptying and performance. The 3D lesson here represents the current-wheel principle; it should not be read as the design of a particular surviving overshot wheel.
Measuring performance
The Science Museum Group holds a modern model of John Smeaton’s apparatus for investigating waterwheel efficiency, identifying the original apparatus with 1752 and John Horniblow’s model with 1988. Keeping these dates separate matters: a later teaching reconstruction can preserve information about an experiment without itself being the eighteenth-century apparatus. Mechanical explanation and an object’s provenance are complementary forms of evidence.
Every part, in words
Paddles. In a current wheel, flowing water acts on blades near the bottom. This differs from feeding water over the top of an overshot wheel.
Axle. The axle carries the wheel’s rotation onward. Real installations used transmissions to drive machinery.
Channel. A water source and its flow constrain a mill. The flat blue surface is a schematic marker, not simulated flow.