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 see that day and night, and the four seasons, repeat in cycles, and to describe how the light and heat from the Sun change through the day and the year. The museum offers one example of people dividing daylight and darkness into hours; the class observes its own sky and weather. 1
Curriculum expectations, with their official codes
- E2.2 demonstrate an understanding that a cycle is a series of repeating events, and that cycles can be observed in daily and seasonal changes
- E2.3 describe the changes in the amount of light and heat from the Sun that occur throughout the day and in the four seasons
2 The lesson
What repeats, and what changes each time?
Notice when it gets light and when it gets dark where you live. Ask what is the same from one day to the next, and what is different from one season to the next.
Go deeper
Al-Jazari's castle clock opens doors and drops balls from the beaks of two falcons 2. It divides daylight into twelve parts and darkness into twelve. Their lengths change with the seasons, so a seasonal hour is not always sixty minutes 3. At night, lit roundels show the parts going by 4. A person has to return the water and reset the parts for the next cycle 4.
Think about it
Daylight is cut into twelve parts, and so is darkness. Think about where you live. In which season would a daytime part be longer than a night part, and why?
Into the museum
- The castle clock: doors, falcons and many signals of the time in one machine.
- The elephant clock: another clock from al-Jazari's book, with a rider, a bird, a dragon and a gong.
- Al-Jazari: the engineer who wrote the book.
Try this
Write down the time of sunrise and sunset on one day this week. Next month do it again and compare. Then read the card on this page about al-Jazari's twelve portions of daylight.
3 Check yourself
Nothing here is marked or sent anywhere. It is for you.
In your own words: what does Al-Jazari's castle water clock have to do with this lesson?
Compare with the card
Twelve portions of daylight. Al-Jazari's castle clock divides daylight into twelve portions and darkness into twelve, although their lengths change seasonally. Why does a portion of daylight get longer and shorter through the year?
I can now
Notes
- 1. Ontario Ministry of Education, The Ontario Curriculum: Science and Technology, Grades 1–8 (2022)
- 2. MFA Boston: castle-clock painting14.533, catalogue
- 3. Al-Jazari — Donald Hill translation1974, pp.17–18,editor-notes-I.1
- 4. Al-Jazari — Donald Hill translation1974, pp.39–41