Draft: this lesson was written with AI help and has not yet been read by a human editor.
1 What your class asks
This lesson asks you to describe how mechanisms pass different kinds of motion, including rotary motion, from one system to another, and how they change that motion: its plane, its speed or its direction. The museum offers two water-lifting machines described in one medieval book; the forces in them, and machines of your own, are for your class. 1
Curriculum expectations, with their official codes
- D2.3 describe how different mechanisms transmit various types of motion, including rotary motion, from one system to another
- D2.4 describe how mechanisms transform motion, including how they can change the geometric plane in which the motion occurs and the speed and/or direction of motion
2 The lesson
Where does the motion change its kind?
The expectations ask how motion is passed on and changed. Follow the motion from the part that is driven to the part that does the work, and mark every place where it turns into a different kind of motion.
Go deeper
In the fifth division of al-Jazari's book, which deals with water-raising devices, an animal's movement turns the driving pole and supplies the energy for the scoop lifter 2 3. A pin on a rotating part moves in a slot in the ladle's stem and drives it up and down, rather than carrying the ladle round in a circle 2. So the scoop descends, collects water and rises again 2 3. The record calls this a conversion from the animal's rotation to a back-and-forth movement of the water carrier 2.
Think about it
In the scoop lifter the pin slides in a slot in the ladle's stem. What would the ladle do if the pin were fixed to the stem and could not slide, and why?
Into the museum
- The animal-powered scoop lifter: gears, a pin and a slot, step by step.
- The double-piston pump: another machine from the same book, driven by flowing water.
- Al-Jazari: the engineer and the six divisions of his book.
Try this
Read about the double-piston pump and the animal-powered scoop lifter. Draw each as a chain of boxes from the source of power to the water, and mark where turning motion becomes back-and-forth motion.
3 Carry it further
Where this lesson leads in the museum.
4 Check yourself
Nothing here is marked or sent anywhere. It is for you.
In your own words: what does Al-Jazari's waterwheel-driven double-piston pump have to do with this lesson?
Compare with the card
A pump driven by a stream. Al-Jazari described a pump powered by flowing water. According to the TDV encyclopedia, a stream drives a wheel and gears, and a pin with a slotted rod converts the rotation into back-and-forth motion in the arms of two pistons. Where does the motion change its kind?
In your own words: what does Al-Jazari's animal-powered scoop water-lifter have to do with this lesson?
Compare with the card
A pin in a slot, again. Chapter V.4 of al-Jazari's book describes a water lifter turned by an animal. Gears carry the rotation to a pin that moves inside a slot in the ladle stem, raising and lowering the scoop. The record makes no claim that he was the first, and says a folio at the Metropolitan Museum is a later copy, not a surviving machine. How is this pin and slot like the pin and slot of the pump?
I can now