unit 4 lesson 1 part ii earth’s days, years, and...
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Unit 4 Lesson 1 Part II Earth’s Days, Years, and Seasons
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Seasons change …
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What causes seasons?
• Most locations on Earth experience seasons. Each season is characterized by a pattern of temperature and other weather trends.
• We experience seasons due to changes in the
intensity of sunlight and the number of daylight hours as Earth revolves around the sun.
Unit 4 Lesson 1 Earth’s Days, Years, and Seasons
What causes seasons?
• At an equinox, sunlight shines equally on the Northern and Southern hemispheres. Half of each hemisphere is lit, and half is in darkness.
• As Earth moves along its orbit, the sunlight
reaches more of one hemisphere than the other. • At a solstice, the area of sunlight is at a
maximum in one hemisphere and at a minimum in the other hemisphere.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 1 Earth’s Days, Years, and Seasons
What causes seasons?
• During the September equinox, sunlight shines equally on both poles.
• During the March equinox, half of each
hemisphere is lit, and the sunlight is centered on the equator.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 1 Earth’s Days, Years, and Seasons
What causes seasons?
• At the December solstice, the North Pole leans away from the sun and is in complete darkness, and the South Pole is in complete sunlight.
• At the June solstice, the North Pole leans toward
the sun and is in complete sunlight, and the South Pole is in complete darkness.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 1 Earth’s Days, Years, and Seasons
What causes seasons?
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 1 Earth’s Days, Years, and Seasons