SC.E AA The student knows that the tilt of the Earth on its own axis as it rotates and revolves around the sun causes changes in season, length of day, and energy available. Content Limits: Items will assess one concept (i.e., night and day, seasons, length of day, or energy available) at a time.

Day and Night Earth spins from west to east (counter clockwise) on its axis, an imaginary line that runs from the North Pole to its South PoleEarth spins from west to east (counter clockwise) on its axis, an imaginary line that runs from the North Pole to its South Pole Each complete spin, or rotation, takes about 24 hoursEach complete spin, or rotation, takes about 24 hours Earth is tilted on its axis at an angle of 23.5°Earth is tilted on its axis at an angle of 23.5° Because of Earth’s tilt, its northern hemisphere tilts toward the sun during the summer. This results in longer periods of daylight.Because of Earth’s tilt, its northern hemisphere tilts toward the sun during the summer. This results in longer periods of daylight.

Revolution and Seasons Revolution is Earth moving around the sun, once each year (365 days, 5 hours, 48 minutes, and 46 seconds)Revolution is Earth moving around the sun, once each year (365 days, 5 hours, 48 minutes, and 46 seconds) Leap year: occurs every four years when one day is added to February due to Earth’s revolutionLeap year: occurs every four years when one day is added to February due to Earth’s revolution The path a moon or planet follows is called its orbit. The Earth has an elliptical orbit.The path a moon or planet follows is called its orbit. The Earth has an elliptical orbit.

The Earth’s tilted axis as it revolves around the sun produces the seasonsThe Earth’s tilted axis as it revolves around the sun produces the seasons The day when the amount of daylight is the greatest is called the summer solstice (June 21 – Northern Hemisphere)The day when the amount of daylight is the greatest is called the summer solstice (June 21 – Northern Hemisphere) Winter solstice, the day with the least amount of daylight is December 21 (Northern Hemisphere)Winter solstice, the day with the least amount of daylight is December 21 (Northern Hemisphere) Days when the Earth is not tilted toward the sun are called equinoxes (March 21 and September 21)Days when the Earth is not tilted toward the sun are called equinoxes (March 21 and September 21)

Seasons are opposite in the southern hemisphere. Seasons are opposite in the southern hemisphere. Summer does NOT occur because the Earth is closest to the sun. In fact, Earth is closest to the sun in January and farthest away in July. Summer does NOT occur because the Earth is closest to the sun. In fact, Earth is closest to the sun in January and farthest away in July.

Energy Available The sun’s rays hit the Northern Hemisphere more directly during the summer.The sun’s rays hit the Northern Hemisphere more directly during the summer. During the winter, the sun’s rays are at an angle and spread out causing less heating of the surface.During the winter, the sun’s rays are at an angle and spread out causing less heating of the surface.