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 use units of time, such as seconds, minutes, hours and units you make up, to say how long different events last. The museum offers one old clock that marked time in half hours; the clocks, the timings and the units you make up your class brings. 1
Curriculum expectations, with their official codes
- E2.4 use units of time, including seconds, minutes, hours, and non-standard units, to describe the duration of various events
2 The lesson
Which unit fits the event?
Think of a clap, a lunch and a school day. Say whether each is best told in seconds, minutes or hours, and why.
Can you make your own unit?
Count how many times you can bounce a ball before a minute passes, and use "one bounce" as a unit to tell how long something lasted.
Go deeper
Imagine a machine that tells you a half hour has passed. The Met's catalogue describes the elephant clock in al-Jazari's book: every half hour figures move, a ball drops and a sound is heard 2. A ball passes from falcon to dragon to a vessel containing a gong, and counting accumulated balls indicates elapsed time 2. The record adds that the elephant is a machine's shape in al-Jazari's book, and the picture a later copy, not a living animal or a photograph of his original clock 3.
Think about it
This clock gives a signal that can be seen and heard every half hour. Why might that help someone who is busy with other work?
Into the museum
- The elephant clock: how its figures, balls and gong show a half hour.
- Al-Jazari: the author of the book in which the clock is described.
Try this
Read the record on the elephant clock. Drop a counter into a cup every time a half minute passes, and use the counters to say how long a short song lasts.
3 Check yourself
Nothing here is marked or sent anywhere. It is for you.
In your own words: what does Al-Jazari's elephant clock have to do with this lesson?
Compare with the card
A clock that marks every half hour. Every half hour figures move, a ball drops and a sound is heard: this is how the Met's catalogue describes the elephant clock in al-Jazari's book. The rider strikes the elephant, the bird moves and a ball passes from falcon to dragon to a vessel containing a gong; counting the accumulated balls indicates elapsed time. How long would it take for ten balls to gather?
I can now