Seasons Benchmark SC Describe how the Earth's motions and tilt on its axis affect the seasons and weather patterns SC.8.8.3

SWBAT SWBAT explain the factors that influence seasonal change and identify the seasons of different geographic regions. SWBAT explain the factors that influence seasonal change and identify the seasons of different geographic regions. Benchmark SC Describe how the Earth's motions and tilt on its axis affect the seasons and weather patterns Benchmark SC Describe how the Earth's motions and tilt on its axis affect the seasons and weather patternsSC.8.8.3

Vocabulary Lesson Before we begin our discussion on ‘Seasons’ we need to understand the difference between two terms. REVOLUTIONandROTATION

Vocabulary Lesson REVOLUTION – when a moon or planet travels once around another object, this is a revolution. Example: A complete trip of the Earth around the sun

Model of the Seasons

Quick Challenge Question: Name ONE limitation of the model below.

Which planet has the SHORTEST revolution? Longest?

Vocabulary Lesson ROTATION – a circular movement of an object around a center (or point) of rotation. Example: When the Earth makes a complete trip on its axis from west to east

Rotation

How about a song to help remember the difference?

Seasons Outside the Tropical zone, most places have four seasons: winter, spring, summer, and autumn. Outside the Tropical zone, most places have four seasons: winter, spring, summer, and autumn. The North and South Hemisphere have opposite seasons. The North and South Hemisphere have opposite seasons. Hmmm… Hmmm… Why would the Northern and Southern Hemisphere have opposite seasons? Why would the Northern and Southern Hemisphere have opposite seasons?

Yes! Tilted Axis of Earth Seasons are caused by the tilt of Earth’s axis as the Earth travels around the Sun. Seasons are caused by the tilt of Earth’s axis as the Earth travels around the Sun. So when the Northern Hemisphere is tilted toward the Sun it gets __________________________and while the Southern Hemisphere is tilted away from the Sun _________________________________ So when the Northern Hemisphere is tilted toward the Sun it gets __________________________and while the Southern Hemisphere is tilted away from the Sun _________________________________

Good… so this is what the earth’s axis looks like, right?

WRONG!

Earth’s Axis: Not So Straight! The earth’s axis is tilted about 23.5 degrees from vertical. The earth’s axis is tilted about 23.5 degrees from vertical. 23.5˚ Axis

Earth’s Axis: Not So Straight! The earth’s axis is tilted about 23.5 degrees from vertical. The earth’s axis is tilted about 23.5 degrees from vertical. 23.5˚ Axis

Look at the Polar zones at the Arctic and Antarctic circle

The Polar Experience When it is Summer in the Northern Hemisphere, the Polar zone in the Northern Hemisphere experiences daylight for 24 hours a day. When it is Summer in the Northern Hemisphere, the Polar zone in the Northern Hemisphere experiences daylight for 24 hours a day. Based on the picture, the Polar zone in the Southern Hemisphere is tilted away from the Sun, so it will get total darkness 24 hours a day. Based on the picture, the Polar zone in the Southern Hemisphere is tilted away from the Sun, so it will get total darkness 24 hours a day. The opposite happens when it is Winter in the Southern Hemisphere. The opposite happens when it is Winter in the Southern Hemisphere.

How the Earth moves around the Sun As the Earth travels around the sun it keeps the same tilt. As the Earth travels around the sun it keeps the same tilt. So, when the North Pole is tilted toward the Sun in the summer it is tilted away from the Sun in the winter. So, when the North Pole is tilted toward the Sun in the summer it is tilted away from the Sun in the winter.

Angle of Sunlight The amount of direct sunlight is CONTINGENT on the tilt of the axis. The amount of direct sunlight is CONTINGENT on the tilt of the axis. As direct rays of sunlight increase, temperature _____________________ As direct rays of sunlight increase, temperature _____________________

Let’s take a closer look: