Waterwheels

An early way of generating power was by a waterwheel. The waterwheel was the earliest replacement of animal and human power. There were different styles of waterwheels as well as different uses of them.

The earliest recorded waterwheels were in ancient Greece in 4000 BC, and were used for irrigating crops, grinding grain, supplying water to villages and making sawmills work. Later on water wheels powered industries such as cloth making or papermaking.

A waterwheel was a very large wooden or metal wheel with a number of blades or buckets on the outside rim. The force of the water moved the blades, which in turn moved the wheel. The movement of the wheel’s axle made machinery inside the mill work.

A flowing stream was sometimes dammed to maintain a steady supply of water for a waterwheel. The dammed water was called a mill pond. A channel was made for the water to flow through on its way to or from the wheel. This was called a mill race, or just race. The channel taking water to the wheel was a headrace, the water leaving the wheel was the tailrace.

Some waterwheels were called undershot waterwheels: the water moved the wheel from the bottom. These waterwheels were cheaper and easier to build, but were not as powerful.

Another kind of waterwheel was called an overshot waterwheel. Water was channelled to the top of the wheel, and poured down to fill buckets on the waterwheel. The buckets being filled were heavier than the empty buckets and this weight made the wheel turn. The water emptied into the tailrace. This kind of waterwheel did not need such a rapidly flowing stream to move it.

Waterwheels often powered mills to grind grain into flour. The water turned the wheel, which turned an axle (called a drive shaft), which then made a vertical cog turn. The teeth of the cog connected with the teeth of a horizontal cog called a lantern gear. The lantern gear made a spindle rotate. Attached to the spindle were two big heavy stones called millstones which moved to grind grain into flour.