Shaduf – Ancient water lifting device

For each Shaduf – 2.5mtr pole of around 4cms thickness. Sandbag and bucket of sand. 8 x 1mtr poles with a pointed end and mallets. 1.2mtr lengths of 3 ply twine. A plastic bucket, and a larger water-tight container such as a plastic storage box filled with water.

1. Shaduf. The challenge is to make a counter-weighted lever to raise a bucket of water by 1 metre.
2. Explain how a shaduf works. Explain the importance of the weighted counterbalance, such that a small amount of force can lift a heavy weight. Problems to overcome – the bucket should be designed to tip and sink when it enters the water in order to fill. Issue shaduf illustrations. Note how a rope is used to pull up the lever arm and control the descent.
3. Make a shaduf. Divide into teams. Each team makes a shaduf. Begin by making two tripods with a clear 45cms between them. Link with a pole that will act as a fulcrum. Firmly tie the lifting arm to the centre of the fulcrum (crossbar). Fill the sandbag with sand and tie the filled bag firmly to the lifting side of the lever. Next, tie on a bucket, ensuring that it tips readily when reaching the water.

Before use, ensure the supporting frame is sufficiently sturdy. Brace with guy ropes to ensure stability.