Sun Earth Moon Light Warmth Energy Tidal Phase Seasonal Changes Chapter 28, Section 28.3 We, benefit from the Earth’s relationship with the Sun and Moon in many ways, some of which we are unaware of and take for granted… Light Warmth Energy Tidal Phase Seasonal Changes Calendar Time

MOTION – Earth’s Rotation Sun Earth Moon Chapter 28, Section 28.3 MOTION – Earth’s Rotation Daily rising and setting Sun Moon Stars All rise in the east and set in the west Not all rotate about the Earth Our observation is from a moving Earth Rotates on its axis once per day 15° per hour Solar Day How do we know this? Foucault Pendulum Coriolis Effect

ANNUAL MOTION – Effect of Earth’s Tilt Sun Earth Moon Chapter 28, Section 28.3 ANNUAL MOTION – Effect of Earth’s Tilt Earth’s Tilted Axis Weather Change Length of Day Temperature Change The Earth orbits the Sun via an elliptical plane Earth’s tilt on its axis is 23.5° The axis remains fixed in its orientation This changes the distance a hemisphere is from the Sun Changes the altitude of the Sun in Earth’s sky Completed changes are approximately every six months

SOLSTICES – Winter and Summer Sun Earth Moon Chapter 28, Section 28.3 SOLSTICES – Winter and Summer Twice a Year Sun reaches Northern and Southern Extremes Over the Tropic of Cancer @ 23.5° N (Summer ~ June 21) Over the Tropic of Capricorn @ 23.5° S (Winter ~ December 21) Sun is at its greatest distance from the equator. In the Southern Hemisphere, the winter and summer solstices are reversed.

EQUINOX – Vernal and Autumnal The Sun’s rays strike the equator at Sun Earth Moon Chapter 28, Section 28.3 EQUINOX – Vernal and Autumnal The Sun’s rays strike the equator at 90° Vernal – March 21 or 22 Autumnal – September 22 or 23 When the Sun is directly over the equator The hemispheres receive equal amounts of sunlight Day an Night are equal in duration The term EQUINOX means “EQUAL NIGHTS”

Sun Earth Moon Chapter 28, Section 28.3

MOON PHASES – What We See and Why Sun Earth Moon Chapter 28, Section 28.3 MOON PHASES – What We See and Why Let us examine the moons cycle this way… New moon and Full moon 1st quarter and 3rd quarter The phases in between

MOON PHASES – What We See and Why Sun Earth Moon Chapter 28, Section 28.3 MOON PHASES – What We See and Why New Moon and Full Moon The “New Moon” occurs when the Moon is positioned between the Earth and Sun illuminating the back side of the moon, the half that we cannot see. The “Full Moon” occurs when the Moon is on the opposite side of the Earth, so the entire sunlit part of the moon is facing us.

MOON PHASES – What We See and Why 1st Quarter and 3rd Quarter Moon Sun Earth Moon Chapter 28, Section 28.3 MOON PHASES – What We See and Why 1st Quarter and 3rd Quarter Moon The 1st and 3rd quarter, each is often called a "half moon“, occurs when the moon is at a 90° angle with respect to the earth and sun. We are half illuminated and half in shadow.

MOON PHASES – What We See and Why Sun Earth Moon Chapter 28, Section 28.3 MOON PHASES – What We See and Why Other Phases Crescent is a phase of less than half illumination. Gibbous is a phase of more than half illumination. Waxing means expanding in illumination. Waning means decreasing in illumination.

MOON ORBIT – Synchronous Rotation and Tides Sun Earth Moon Chapter 28, Section 28.3 MOON ORBIT – Synchronous Rotation and Tides Only one face of the Moon is visible to us This is because of the speed at which the Moon now rotates Millions of years ago it spun faster Slowed by the gravitational influence of the Earth The smaller gravitational influence of the Moon create tides Rise and fall of water level to the shore every 12 hours Twice the influence on tides as that of the Sun