The Reasons for Seasons

Students learn that Earth's 23.5 degree axial tilt, not its distance from the Sun, causes the seasons by changing the angle of sunlight and the length of the day through the year.

Grades 5-8About 15 minutes of narrated flight, plus discussion stops7 stops

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What students will see and do

Students visit the Sun to test the distance myth, fly to Polaris to see where Earth's axis points, and circle Earth five times to study tilt, direct and slanted light, day length, solstices and equinoxes, and opposite seasons. The class pauses at two discussion stops: the Sun and Polaris.

Learning objectives

• Use the dates of Earth's closest and farthest points from the Sun to refute the idea that distance causes seasons.
• Model how a fixed axial tilt makes each hemisphere lean toward and away from the Sun during one orbit.
• Explain how the angle of sunlight and the number of daylight hours together control seasonal heating.
• Identify the solstices and equinoxes and describe where the noon Sun is overhead on each.

NGSS connections

Stops on this journey

1. The Distance Myth (discussion stop)
2. A Tilted Planet
3. Aiming at the North Star (discussion stop)
4. Direct and Slanted Sunlight
5. Long Days and Short Days
6. Solstices and Equinoxes
7. Opposite Seasons and Other Worlds

Vocabulary

• axial tilt
• axis
• hemisphere
• solstice
• equinox
• direct sunlight
• seasonal lag
• precession