Why Do We Have Seasons? (explained in 1 minute)
Why summer and winter happen: Earth's tilted axis, direct and slanted sunlight, and why the two hemispheres have opposite seasons.
- Subject: Science
- Age group: 10-14
What this video covers
- Earth’s tilt and its orbit around the Sun cause the changing seasons, while the axis keeps nearly the same direction.
- The hemisphere tilted toward the Sun receives more direct sunlight for more hours, producing summer.
- The opposite hemisphere receives lower-angle sunlight for fewer hours, producing winter, and the hemispheres swap roles six months later.
- Spring and autumn occur between the strongest tilt positions, and both hemispheres share one orbit while experiencing opposite seasons.
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Transcript
Seasons happen because Earth is tilted as it travels around the Sun. Earth’s axis leans about twenty-three and one-half degrees, and it keeps pointing in nearly the same direction during the year.
When your part of Earth is tilted toward the Sun, sunlight hits it more directly. The Sun also stays above the horizon for more hours, so that half of Earth gets more energy each day. These conditions make summer.
At the same time, the opposite hemisphere tilts away. Its sunlight arrives at a lower angle and spreads over a larger area, while its days are shorter. That makes winter there. Six months later, the hemispheres trade roles.
Spring and autumn happen between these positions, when neither hemisphere leans strongly toward or away from the Sun. Seasons are not caused mainly by Earth being closer to the Sun. Both hemispheres follow one orbit but have opposite seasons.