Flowing water has been used for thousands of years to power all sorts of machines and to do all sorts of useful things. Waterwheels were used for many years to provide the power for factories until the mighty and more reliable steam engine began to be used in the late 1700’s and early 1800’s.
These water wheel models are quite easy to make and it’s great fun experimenting with different paddle shapes. The paddles are cut from plastic milk bottles using normal classroom scissors. Can you see how the different shaped paddles have been made by cutting out certain sections of the bottles? Slits are cut into the plastic foam wheel and the paddles are pushed in. The support is a strip of wood which can be pushed into the ground or into a wooden base with hole. The rectangular block has holes pierced in it to accept the support strip and the wooden axle for the wheel. The block can be moved to any height on the support.
Pupils are challenged to adapt and even redesign the waterwheel so that it becomes a garden novelty for example. This model winds up a string as the water wheel turns. If card is used then it can be laminated to make it waterproof!
These pictures and video clip show how a reservoir of water is attached at the top of the support strip using tape (and a cable tie if required). The reservoir slowly releases water via the tube to fill a ‘bucket’ or push against paddles.
Click pic for video clip
The reservoir can be modified to make an ‘automatic release syphon’. This is a fantastic addition because the water doesn’t run from the reservoir until the water level in the reservoir is near to being the maximum. This means that you can leave the novelty out in the rain and when the reservoir becomes filled the waterwheel or novelty starts to operate. If a syphon reservoir is not used then the water simply starts running out immediately so it’s not likely that a rain shower will make it work because the actual water flow is likely to be too ‘weak’.
Water power is a fascinating topic. Other possible models include an Egyptian Shaduf and an Archimedean screw’ water pump. I’ll try to add these soon.