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Egyptian Shaduf

From DT Online

Shaduf


Description

A Shaduf (aka Shadoof) is hand-operated simple machine for lifting water to irrigate land still used in India, Africa, Egypt, and some other countries. Typically it consists of a long pole or beam mounted like a tall seesaw. There is a water bucket suspended from one end and a counterweight is positioned towards the other.


EgyptianShaduf.png

In use, the water bucket suspension rope is pulled down to lower the bucket into the water and then lifted out with the aid of the counterweight when filled. In both actions, the top beam serves mainly as a Class 1 Lever: pulling against the counterweight as the bucket is lowered and, as it is raised, the counterweight provides the Effort to lift the weight of water (plus a little extra effort provided by the operator pulling the bucket upwards).


Task
  • Build a model Shaduf and use it to lift a 1kg mass.
    • use Stripwood to build the main frame.
    • you may wish to fill part of the lid from a spray can or a paper cup with ‘plasticine’ or similar to make a counterweight.
    • the top of a spray can or a paper cup may also be used to model a water bucket.


Testing
  • How does the Shaduf make it easier to lift the mass?
  • Does it matter where you position the counterweight?
  • Should the counterweight balance an empty bucket or a bucket filled with water - or half filled with water?
  • How heavy would the counterweight be to lift a litre of water?
  • How might the design limit the height to which pyramid stones could have been lifted in this way?
  • How would you make a larger model using garden canes for example?


DT Online Buyers' Guide

Safety Point! Take great care with hot glue guns and all hot-melt glues. The melted glue can stick to the skin and cause severe burns.


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Stanley Junior Hacksaw 0 15 218 Draper 14145 55 mm Clamp-On Hobby Bench Vice 5 x Richard Burbidge Decorative Wood Stripwood - Pine - 900 x 8 x 8mm Balsa Wood - Giant Pack House of Card & Paper A4 220 gsm Card - Assorted Bright (Pack of 100 Sheets) 100 sheets coloured card mix A4 300gsm thick card Am-Tech A3 Cutting Mat Chartwell A3 Orange Student Graph Pad 50 Sheets (1, 5 & 10mm Grid Paper) J13B 4 PVA Glue Washable Adhesive School Home Crafts Non Toxic Wood Paper Fabric Art Bosch PKP 18 E Glue Gun Strong Heavy Duty Professional Bamboo Plant Support Garden Canes | 2ft - 10ft