Day, night and the seasons

Brief

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

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.