Seasons

Definition

The seasons are divisions of the year marked by specific weather conditions, daylight hours, and ecological changes. They result from Earth's tilt on its axis and its orbit around the Sun.

5 Must Know Facts For Your Next Test

1. The tilt of Earth's axis is approximately 23.5 degrees.
2. Seasons are opposite in the Northern and Southern Hemispheres.
3. The summer solstice occurs when one of Earth's poles has its maximum tilt toward the Sun.
4. Equinoxes occur when day and night lengths are approximately equal worldwide.
5. Earth's elliptical orbit causes slight variations in seasonal length.

Review Questions

• What causes the different seasons on Earth?
• Why are seasons opposite in the Northern and Southern Hemispheres?
• When do equinoxes occur and what happens during them?

Related terms

Axial Tilt: The angle between an object's rotational axis and its orbital axis; for Earth, it is about 23.5 degrees.

Solstice: Either of the two times in the year when the Sun reaches its highest or lowest point in the sky at noon, resulting in the longest and shortest days.

Equinox: Occurs twice a year when day and night are nearly equal in length due to Earth's tilt being perpendicular to its orbit around the Sun.