Twisted rope skeins and archimedes’ screw: what they have in common

1. Step 1. Twisted rope skeins — is part of — Catapult. Twisted skeins store energy.
2. Step 2. Catapult — evolved into — Trebuchet. The trebuchet replaced torsion engines as a more powerful siege machine.
3. Step 3. Trebuchet — uses — Counterweight. A falling counterweight swings the throwing arm.
4. Step 4. Counterweight — is used in — Shaduf. The counterweight makes lifting the bucket easier.
5. Step 5. Shaduf — is used in — Irrigation. The shaduf fed water into the canals.
6. Step 6. Irrigation — uses — Archimedes’ screw. The Archimedes’ screw lifted water for irrigation.

Open Evothings