Moon Phases

Vocabulary To Help• Revolution – the motion of the moon around

Earth, one complete orbit• Phase – the shape of the moon as seen from the

Earth• Waxing-describes a moon that seems to be

getting bigger each night• Waning – describes a moon that seems to be

getting smaller each night• Crescent – a moon that is smaller than a quarter

moon, but larger than the new moon• Gibbous – a moon that is larger than a quarter

moon, but smaller than a full moon

Half of the Moon is always lit up by the sun. As the Moon orbits the Earth, we see different parts of the lighted area.

http://www.nasm.si.edu/apollo30th/moontheater/phasepage2.html

The revolution of the Moon around the Earth makes the Moon look as if it is

changing shape in the sky. 

http://btc.montana.edu/ceres/html/birthdayphases.htm

This is caused by the different

angles from which we see the

illuminated part of the Moon's

surface.  These are called

"phases" of the Moon. 

http://btc.montana.edu/ceres/html/birthdayphases.htm

• The phase you see when you look at the moon depends on its location in relationship to the sun and Earth

• The moon doesn’t create any light itself; it just reflects the light of the sun.

http://www.niehs.nih.gov/kids/lunar/why_phases.gif

The Moon passes through eight major shapes during a cycle that repeats itself every 29.5 days.  The phases

always follow one another in the same order:

New Moon

The moon is lined up between the Earth and the Sun almost in a straight line

•The illuminated half of the moon is facing away from the Earth, and therefore the part that is facing us is all dark

•The moon and the Sun rise and set at about the same time

New Moon

Waxing Crescent Moon

As the moon moves around the Earth, we see more and more of the illuminated half•This Moon can be seen after the New Moon, but before the First Quarter Moon.•It looks as if the moon is getting bigger each night.•The moon is smaller than a quarter moon.•The moon is waxing (increasing or growing)

http://btc.montana.edu/ceres/html/birthdayphases.html

Waxing Crescent Moon

http://btc.montana.edu/ceres/html/birthdayphases.html

First Quarter Moon• A week after the new moon, when the

Moon has completed about a quarter of its turn around the Earth, we can see half of the illuminated part.

• From Earth, we are looking at the sunlit side of the Moon from off to the side.

• The right half of the Moon appears lighted and the left side of the Moon appears dark. 

• A quarter of the moon

First Quarter Moon

Waxing Gibbous Moon

• During the next week, we keep seeing more and more of the illuminated part of the Moon making it appear to grow larger and larger every day.

• Waxing gibbous– Gibbous means “humped”. 

http://btc.montana.edu/ceres/html/birthdayphases.html

Waxing Gibbous Moon

http://btc.montana.edu/ceres/html/birthdayphases.html

Full Moon• Two weeks after the new moon, the moon

is now halfway through its revolution of the Earth.

• The illuminated half of the Moon is facing the Earth. 

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

• At this time the Moon rises at the time the Sun sets and it sets when the Sun rises.

Full Moon

Waning Gibbous Moon

• This Moon can be seen the first week after the Full Moon, but before the Last Quarter Moon. 

• From this point, until it becomes new again, the illuminated part of the Moon that we can see gets smaller.

http://btc.montana.edu/ceres/html/birthdayphases.html

Waning Gibbous Moon

http://btc.montana.edu/ceres/html/birthdayphases.html

Last (Third) Quarter Moon

• Three weeks after the new moon, we again can see half of the illuminated part.

• The left half of the Moon appears lighted, and the right side of the Moon appears dark. 

Third Quarter Moon

Waning Crescent Moon

• This Moon can be seen after the Last Quarter Moon and before the New Moon. 

• During the fourth week, the crescent moon will appear to get smaller and smaller

http://btc.montana.edu/ceres/html/birthdayphases.html

Waning Crescent Moon

http://btc.montana.edu/ceres/html/birthdayphases.html

http://www.opencourse.info/astronomy/introduction/04.motion_moon/moon_phases.gif

Waxing & Waning

http://www.nasm.si.edu/apollo30th/moontheater/phasepage4.html

http://www.nasm.si.edu/apollo30th/moontheater/phasepage4.html

http://www.calvin.edu/~lmolnar/moon/images/phases.gif

Moon Movie

The movie is an animated GIF created by Antonio Cidadao from a sequence of still images taken during March and April 1998. Copyright Antonio Cidadao.

http://aa.usno.navy.mil/faq/docs/moon_phases.html

MOON QUIZ!!

http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/

moonlight.html