A machine for washing hands

This lesson asks you to identify machines used in daily life and describe their purposes, and to identify the parts of mechanisms and describe the purpose of each part. The museum offers one hand-washing device from a medieval book of ingenious devices, described as a design; your class must add machines from its own daily life. ¹

The expectations ask for parts and their purposes. When you meet a device, name each part and say what would stop working if you took it away.

A peacock pours water, a figure offers soap and another a towel: this hand-washing design is in al-Jazari's book. The record explains that when the master wants to wash, the servant brings the basin with the peacock's head facing him and stands aside as the service begins ². Collected water raises a float and a figure offers soap; more water brings a figure with a towel ³. Used water drains through a spigot ³. The museum does not know for certain whether the machine was built ⁴.

In this design the servant carries the basin while the figures offer the soap and the towel. If you were designing a hand-washing station, which jobs would you give to the machine and which to a person, and why?

• Al-Jazari's peacock hand-washing design: the float, the doors and the used-water spigot, stage by stage.
• Al-Jazari: the engineer who described it, and the other devices in his book.

Read about al-Jazari's peacock hand-washing design. Make a table with the peacock, the float, the two figures and the spigot, and write one job for each.