GED Science TestEarth and Space ScienceMedium
A homeowner is considering installing solar panels. They live in a region that experiences significant seasonal variations in sunlight hours. Which of the following Earth movements is primarily responsible for these seasonal changes in the amount of solar energy received at different latitudes?
- AThe tilt of the Earth's axis relative to its orbital plane.
- BVariations in the Earth's orbital speed throughout the year.
- CThe Earth's rotation on its axis.
- DThe Earth's revolution around the Sun.
Show answer & explanationAnswer & explanation
Correct answer: A. The tilt of the Earth's axis relative to its orbital plane.
The tilt of Earth's axis (approximately 23.5 degrees) relative to its orbital plane causes different parts of the Earth to receive more direct sunlight at different times of the year as it revolves around the Sun. This axial tilt is the primary reason for seasonal variations in solar energy and daylight hours.
Why the other options are wrong
- B. Variations in orbital speed (due to elliptical orbit) cause slight changes in solar intensity but are not the primary cause of major seasonal changes.
- C. Earth's rotation causes day and night, not seasons or seasonal changes in solar energy.
- D. While Earth's revolution around the Sun is necessary for seasons, it's the combination with the axial tilt that creates the seasonal variations.
Earth's Axial Tilt
The inclination of Earth's rotational axis relative to its orbital plane, approximately 23.5 degrees, which is the primary cause of seasons.
- Causes direct sunlight to shift between hemispheres throughout the year.
- Leads to variations in daylight hours and solar intensity at different latitudes.
- Without tilt, there would be no distinct seasons.
Memory trick: Tilt Triggers Temperature and Time changes.