Earth Patterns, Cycles, and Change

Rotation• The Earth rotates on its axis every 24

hours.

Revolution• The Earth completes one revolution

around the sun every 365 days.

• Due to its axial tilt, the Earth experiences seasons during its revolution around the sun.

Moon and Earth Relationship• The Moon revolves around the Earth

about once every month.

• During its revolution, we see phases of the moon that are caused by the moon’s position relative to the Earth and sun.

Rotation of the Moon• The Moon always presents the same

face towards Earth.– Another common misconception is that this

means that the Moon does not rotate.– However, in order to keep the same face

toward Earth, the Moon must rotate once every orbit.

– The far side of the Moon is not dark, it gets just as much sunlight as the near side.

Near Side of the Moon

Far Side of the Moon

The Phases of the Moon• Waxing Crescent Waxing Crescent 

• First Quarter First Quarter • Waxing Gibbous Waxing Gibbous 

• Full MoonFull Moon• Waning Gibbous Waning Gibbous 

• Last Quarter Last Quarter • Waning Crescent Waning Crescent 

• New MoonNew Moon

Waxing Crescent

• The Moon is less than ½ illuminated. The Moon is less than ½ illuminated. • It is seen after the New Moon and before It is seen after the New Moon and before

the First Quarter Moon. the First Quarter Moon. • The crescent increases every day until The crescent increases every day until

the First Quarter Moon. the First Quarter Moon. • ““Waxing” means increasing.Waxing” means increasing.

First Quarter Moon

• The moon appears to be ½ illuminated. The moon appears to be ½ illuminated. • The right side is light and the left side is The right side is light and the left side is

dark. dark. • The illuminated side grows larger every The illuminated side grows larger every

day until the Full Moon.day until the Full Moon.

Waxing GibbousWaxing Gibbous

• The Moon appears more than ½ but The Moon appears more than ½ but less than fully illuminated. less than fully illuminated.

• It is seen after the First Quarter Moon It is seen after the First Quarter Moon and before the Full Moon. and before the Full Moon.

• The Moon continues to increase until The Moon continues to increase until the Full Moon.the Full Moon.

Full MoonFull Moon

• The Moon’s illuminated side faces the The Moon’s illuminated side faces the Earth. Earth.

• The Earth, Sun, and Moon are in a The Earth, Sun, and Moon are in a straight line, with the Earth in the straight line, with the Earth in the middle. middle.

• The Moon’s brightness is from sunlight The Moon’s brightness is from sunlight reflecting off its surface.reflecting off its surface.

Waning Gibbous

• The Moon appears to be more than ½ The Moon appears to be more than ½ but less than fully illuminated. but less than fully illuminated.

• It appears after the Full Moon and before It appears after the Full Moon and before the Last Quarter. the Last Quarter.

• The lighted side decreases each day. The lighted side decreases each day. • ““Waning” means decreasing.Waning” means decreasing.

Last Qaurter

• The Moon is ½ illuminated. The Moon is ½ illuminated. • This Moon is sometimes called the Third This Moon is sometimes called the Third

Quarter Moon. Quarter Moon. • The left side is lighted and the right side is The left side is lighted and the right side is

dark. dark. • The lighted portion of the Moon decreases The lighted portion of the Moon decreases

each day until the New moon.each day until the New moon.

Waning Crescent

• It appears less than ½ illuminated. It appears less than ½ illuminated. • It appears after the Last Quarter Moon It appears after the Last Quarter Moon

and before the New Moon. and before the New Moon. • The crescent decreases each day until The crescent decreases each day until

the New Moon.the New Moon.

New Moon

• The Moon not illuminated side faces the The Moon not illuminated side faces the Earth. Earth.

• The lighted side faces away from Earth. The lighted side faces away from Earth. • The Sun, Earth, and Moon are in a The Sun, Earth, and Moon are in a

straight line, with the Moon in the straight line, with the Moon in the middle. middle.

• The Moon we see is very dark.The Moon we see is very dark.

• “Everyone is a Moon, and has a dark side which he never shows to anybody.”

–Mark Twain

Misconception:Dark Side of the Moon

• The “Dark Side” of the Moon should really be called the “Far Side.”– The far side gets just as much light as the

near side. For example, during a new moon, the near side of the Moon is dark, and the far side of the Moon is fully illuminated!