39
Why do the seasons change?
Textbook: Part 2, pp. 54–57
GoalExplain in simple words why the seasons change; know what causes day and year.
New words
the Earth · Yeraxis · o‘qequator · ekvatorslanting · qiya
Explanation
The Earth spins on its axis, so night and day change. The Earth needs one year to go once around the Sun. The Earth moves tilted a little, so the sun’s rays fall on its surface differently: when the rays fall straight it is hot, when they fall slanting it is cold. That is why the seasons change.
Worked examples
“The Earth and the Sun”. The Earth goes around the Sun. It needs one year to go around once. The Earth also spins on its axis, so night and day change. Because the Earth is tilted a little, the sun’s rays fall on its surface differently. When the rays fall straight it is summer, when slanting it is winter.
Fun fact: near the equator it is always hot, while at the poles the ice does not melt even in summer.
Class activity
Demonstration: in a dark room move a small ball (Earth) around a lamp (Sun) and watch how the light falls.
Practice
1
How long does the Earth take to go around the Sun once?
One year
2
Why do night and day change?
The Earth spins on its axis.
3
What happens when the rays fall straight?
It is hot (summer).
4
And when the rays fall slanting?
It is cold (winter).
5
Which places are always hot?
Near the equator