Page 173 - Science Course 3 (Book 2)

Mo12-L2b: Why Do the Seasons Change?

Key Concept A solstice is a day when Earth’s rotation axis is the
most toward or away from the Sun.
Why Do the Seasons Change?

How does the tilt of Earth’s rotation axis affect Northern hemisphere
Earth’s weather? receives less sunlight

Southern hemisphere
receives more sunlight

December Solstice
The December solstice is on December 21st or 22nd.
On this day

• the north end of Earth’s rotation axis is away from
the Sun;

• days in the northern hemisphere are shortest and
nights are longest, winter begins;

• days in the southern hemisphere are longest and
nights are shortest; summer begins.

There are four days each year when the direction of
Earth’s rotation axis is special relative to the Sun.

Equinox

Solstice Solstice

Equinox

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