1. The Seasons A Northern Hemisphere Perspective

2. The Seasons Definitions Axis: An imaginary axle that passes through the North and South Poles Rotation = 1 day, or one full spin of the Earth around its axis. It rotates counter-clockwise if viewed from above the North Pole Orbit = 1 year (365 ¼ days), or 1 lap around the Sun. Tilt: 23.5° toward the North Star. It rotates counter- clockwise if viewed from above the North Pole Aphelion: Earth is farthest from the Sun (~152 million km or ~94 million miles). Occurs ~July 4 th Perihelion: Earth is closest to the Sun (~147 million km or ~91 million miles). Occurs ~January 3 rd

3. Seasons Tilt Equals Seasons! Seasons change because Earth is tilted toward the North Star while it orbits the Sun. The tilt allows for different parts of the hemisphere to receive different amounts of solar radiation.

4. The Seasons Tilt Equals Season Equinox The 2 days when the Sun’s rays shine straight down on the equator. Equinox means “equal night.” Daylight and nighttime are equally 12 hours long. Spring equinox: (March 21 or 22) Fall equinox: (September 21 or 22))

5. Seasons Tilt Equals Season Solstice Four days in the year are named according to Earth’s location around the Sun. (there are 2 solstices and 2 equinoxes) Summer solstice: (June 21 or 22) is the day when the North Pole leans toward the Sun. Longest day of the year. Winter solstice: (December 21 or 22) i.s the day when the North pole leans away from the Sun. Shortest day of the year.