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“Why are there seasons?”. GEMS Space Science Unit 2. Unit 2 Key Concepts. The distance between the Sun and the Earth is so great if you had the model of the Sun, the size of a pea, on drawn on a piece of paper, the Earth would be off the page. Day and Night Cycle. Unit 2 Key Concepts.
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“Why are there seasons?” GEMS Space Science Unit 2
Unit 2 Key Concepts • The distance between the Sun and the Earth is so great if you had the model of the Sun, the size of a pea, on drawn on a piece of paper, the Earth would be off the page.
Unit 2 Key Concepts • Scientists use models to demonstrate ideas, explain observations, and make predictions.
Unit 2 Key Concepts • Earth travels around the Sun in a nearly circular orbit called an ellipse.
Unit 2 Key Concepts • The Sun is very close to the center of Earth’s orbit.
Unit 2 Key Concepts • Patterns of average-temperature change (and seasons) are opposite for the Northern and Southern Hemispheres.
Unit 2 Key Concepts • Earth’s tilt does not significantly change its distance from the Sun.
Unit 2 Key Concepts • Scientific explanations are based on evidence gathered from observations and investigations.
Unit 2 Key Concepts • For any given latitude, spring and summer days have more hours of daylight, and fall and winter nights are longer.
Unit 2 Key Concepts • In the Northern and Southern Hemispheres, day-length changes (and seasons) are opposite one another during the year.
Unit 2 Key Concepts • Day-length changes are more dramatic farther away from the Equator.
Unit 2 Key Concepts • Earth’s tilted spin axis causes seasonal changes in hours of daylight and night throughout the year.
Unit 2 Key Concepts • At the beginning of summer, sunlight falls at a steep angle and shines most intensely on Earth’s surface.
Unit 2 Key Concepts • At the beginning of winter, sunlight falls at a shallow angle and shines least intensely on Earth’s surface.
Unit 2 Key Concepts • Earth’s tilt causes sunlight to strike the ground at steeper angles in summer and shallower angles in winter.
Unit 2 Summary • The seasons are not caused by variations in Earth’s distance from the Sun. • Earth’s spin axis remains tilted toward Polaris as it orbits the Sun.
Unit 2 Summary • Earth’s tilt does not significantly change its distance from the Sun. • Seasons are caused by Earth’s tilt, which affects the intensity of sunlight and the number of daylight hours at different locations on Earth.
