SOLAR SYSTEM

Detailed explanation-1: -As the earth spins on its axis, producing night and day, it also moves about the sun in an elliptical (elongated circle) orbit that requires about 365 1/4 days to complete. The earth’s spin axis is tilted with respect to its orbital plane. This is what causes the seasons.

Detailed explanation-2: -The tilt of the Earth’s axis is the most important reason why seasons occur. The Earth’s movement around the Sun causes seasons. The Earth is always tilted to one side as it orbits the Sun. So, when the North pole tilts towards Sun, it’s summer in the Northern hemisphere and winter in the Southern hemisphere.

Detailed explanation-3: -The correct answer is Earth’s revolution and inclination of its axis. Seasons change because of the tilt of the Earth and the planet’s movement around the Sun. Earth’s axis is not vertical.

Detailed explanation-4: -Remind students that the two reasons seasons occur are the tilt of a planet’s axis and its orbit around the sun.

Detailed explanation-5: -Tilt and Revolution The north end of the axis is always pointed toward the North Star as the Earth revolves around the sun. This tilt, combined with its revolution around the Sun, causes seasonal changes. (When it’s summer in the northern hemisphere, it’s winter in the southern, and vice versa.)