The Four Seasons The Earths axis is tilted to 23.5 degrees Seasons The Earths axis is tilted at 23.5 This tilt causes the energy from the sun to hit Earth at different angles throughout the year. The Result? SEASONS! Solstice Two days of the year on which the noon sun is directly overhead at either 23.5 North or South latitude Around June 21st, the Sun is at 23.5 North. This marks the summer solstice for the Northern hemisphere and winter solstice for the Southern hemisphere. Around December 21st, the Sun is at 23.5 South. This marks the winter solstice for the Northern hemisphere & summer solstice for the Southern hemisphere Winter: When a hemisphere is tilted away from the sun Summer: When a hemisphere is tilted toward the sun Seasons Equinox Means equal day and equal night During equinox, sun is directly over the equator at noon Vernal (spring) equinox - Occurs around March 21, marks the beginning of spring. Autumnal (fall) equinox Occurs around Sept 21 marking the beginning of fall. The Suns path through the sky Summer Solstice June 21 Sun is at its highest angle in the sky, longest amount of daylight Winter Solstice December 21 Sun is at its lowest angle in the sky, shortest amount of daylight At your request, a study guide Know phases of the moon Know how long it takes the moon to orbit the Earth, Know how length of moon phase cycle (from new moon to new moon) Know what causes the seasons on Earth Know when solstices and equinoxes occur Know Sun-Earth-Moon alignment for each season and tide Know what eclipses are, how they occur Know what causes tides Know the 4 steps in a tidal cycle Know what spring and neap tides are and when they occur Know how to read and interpret a tide cycle graph (see below) Spring tides Occur during full or new moon phase Neap tides Occur during first or third quarter moon phase 1 st Quarter Full Moon New Moon Full Moon 3rd Quarter Spring tides Occur during full or new moon phase Spring Tides Neap Tides Spring Tides High tide Low tide