22.2 – the earth-moon-sun system – part ii

22.2 – The Earth-Moon-22.2 – The Earth-Moon-Sun System – Part IISun System – Part II

Do NowDo NowWhat causes lunar phases?

Do NowDo NowWhat causes lunar phases?◦Result of the motion of the moon and the sunlight that is reflected from its surface.

Key WordKey WordPerigeeApogeeIlluminated

Vocab WordsVocab WordsSolar EclipseLunar Eclipse

Motions of the Earth-Motions of the Earth-Moon SystemMoon SystemEarth has one natural satellite – the moon◦Moon orbits Earth within a period of about a month.◦Perigee – The moon is the closest to Earth

◦Apogee – The moon is the farthest from Earth

◦The motions of the Earth-moon system constantly change the relative positions of the sun, Earth, and moon.◦This results in changes in the appearance of the moon, called the phases of the moon.

02/27/12

http://youtu.be/7vUObZwLJ8A

http://www.youtube.com/watch?v=nXseTWTZlks

Lunar MotionsLunar MotionsSince the moon rotates and

revolves every 27 1/3 days, we only ever see one side of the moon.

Only satellites and Apollo missions have ever seen the back side of the moon.

EclipsesEclipsesEclipses are simply shadow effects.

Solar EclipseLunar Eclipsehttp://

www.youtube.com/watch?v=xwGs8_otT64

Solar EclipseSolar Eclipse http://www.youtube.com/watch?v=XMyqPxFh5Zw&list=PL59BD9065DEAD4B6E

When the moon moves in a line directly between Earth and the sun, it casts a dark shadow on Earth.

Moon must be at a new moon phase and the moon’s orbit must cross the plane of the ecliptic for an eclipse to take place.

http://eclipse.gsfc.nasa.gov/SEdecade/SEdecade2011.htmlNext total for North America is

August 21, 2017

Lunar EclipseLunar Eclipsehttp://youtu.be/2dk--lPAi04http://www.youtube.com/watch?v=0FdeLGpAQwQ

When the moon moves within Earth’s shadow.

Moon must be at a full moon phase and the moon’s orbit must cross the plane of the ecliptic for an eclipse to take place.

More common than solar eclipses.http://eclipse.gsfc.nasa.gov/

eclipse.htmlNext total for North America is

November 13, 2012

Group ActivityGroup ActivityOn page 626, copy and label Figure 15A.