4 seasons #2

Learning objectives

To understand the meaning of the tropics.
To link the alternating seasons to the Earth's axial tilt .
To understand how the duration of daylight changes with the seasons.

The seasons are three-month periods separating the equinoxes (spring, autumn) and the solstices (summer, winter).

The changing seasons are linked to the variation of the Earth's axial tilt comparative to the plane of the ecliptic.
The Earth’s rotation axis is tilted at an angle of 23.5° from the perpendicular in its year-long orbit around the sun. As the tilt is fixed in space, each of the Earth’s poles is alternately exposed more to the sun every six months.

Diagrams are not drawn to scale.