1. Eclipses and Lunar Phases
This powerpoint compiled by the Education Staff at the Lunar and Planetary Institute
Image from
This picture of the Earth and Moon in a single frame, the first of its kind ever taken by a spacecraft, was recorded September 18, 1977, by NASAs Voyager 1 when it was million km (7.25 million miles) from Earth. The moon is at the top of the picture and beyond the Earth as viewed by Voyager. In the picture are eastern Asia, the western Pacific Ocean and part of the Arctic. Voyager 1 was directly above Mt. Everest (on the night side of the planet at 25 degrees north latitude) when the picture was taken.
Created by the Lunar and Planetary Institute
For Educational Use Only
LPI is not responsible for the ways in which this powerpoint may be used or altered.

3. Preliminary Topics
Before students can understand the reason for phases, they need to understand:
The Moon orbits the Earth
The Moon orbit at an angle with respect to the Earth’s orbit around the Sun
The Moon doesn’t shine on its own; it reflects sunlight
The scale of the Moon and Earth’s sizes and distance
Please go through Earth and Moon statistics before trying to cover the reason for phases or eclipses.
Ecliptic plane
Moon’s orbital plane
We highly recommend doing Earth and Moon statistics with workshop participants before doing this powerpoint, if you intend to discuss the reason for phases or eclipses.

4. Phases: Observing and Identifying
New (couple days) Waxing Crescent (several days) 1st Quarter Waxing Gibbous (several days) Full Waning Gibbous (several days) 3rd Quarter Waning Crescent (several days) New
Images from
In some states, young elementary students may be required in their science standards to observe the changing patterns in the Moon’s appearance. Making observations part of the classroom assignments is a fundamental part of this; the students can bring in drawings of the Moon’s appearance on paper or on paper plates, and they can be placed on the wall over a period of 1-2 months. Students can also make phases out of Oreo cookies.

5. Golfball and Blacklight Activity
Phases--Causes
The Sun shines on the Moon.
When the sunlight reflects off the Moon’s far side, we call it a New Moon
When the sunlight reflects off on the Moon’s near side, we call it a Full Moon
Between New and Full, we see parts of the daytime side of the Moon.
It is not appropriate for very young students to try to master the reason for phases; they often do not have the ability to imagine the three-dimensional nature of this. Many adults have fundamental misconceptions regarding the reason for the Moon’s phases.
We conduct an activity with golfballs and blacklights in our workshop here, allowing participants to see “phases”.
Golfball and Blacklight Activity

6. Please do NOT use this to teach phases;
use to test for comprehension
From
Full Moon rises as the Sun sets.
The Full Moon is in mid-sky at Midnight.
Full Moon sets as the Sun rises.
Full Moon cannot be seen during the day.

7. Also from StarChild: http://starchild. gsfc. nasa
starchild.gsfc.nasa.gov/docs/StarChild/questions/phases.html

8. Eclipses
The Sun and Moon occasionally line up so that we have an eclipse.
These eclipses happen every year
To see a solar eclipse, you need to be on a particular part of the Earth
Only after phases have been mastered should you try to teach the reason for eclipses; otherwise, students will often assume that the reason for the Moon’s phases is the Earth’s shadow.
To understand why we have eclipses, we use the golfballs and blacklights, along with an embroidery hoop to model out the changing intersection of the Moon’s orbit with the ecliptic, as the Earth goes around the Sun.

9. When the Earth’s shadow covers the Moon, we have a lunar eclipse
Additional details are at
When the Earth’s shadow covers the Moon, we have a lunar eclipse

10. Three types of Lunar Eclipses
Penumbral lunar eclipse—the Moon only passes through the penumbra of Earth’s shadow
Partial lunar eclipse—part of the Moon passes through the umbra of Earth’s shadow
Total lunar eclipse—the entire Moon passes through the umbra of Earth’s shadow
Who on Earth will be able to see a lunar eclipse?
Anyone who can see the Moon (anyone who is on the nighttime side of the Earth during the eclipse)

11. Images from Fred Espanak and may be found at
Images from Fred Espenak

12. Why is the Moon red during an eclipse?
The Earth’s atmosphere filters some sunlight and allows it to reach the Moon’s surface
The blue light is removed—scattered down to make a blue sky over those in daytime
Remaining light is red or orange
Some of this remaining light is bent or refracted so that a small fraction of it reaches the Moon
Exact appearance depends on dust and clouds in the Earth’s atmosphere

13. Upcoming Lunar Eclipses
June 26, 2010, Partial lunar eclipse (not visible here))
Dec 21, 2010, Total lunar eclipse visible in US just after midnight
June 15, 2011, Total lunar eclipse (not visible in US_
Dec 10, 2011, Total lunar eclipse (not visible in US)
June 4, 2012, Partial eclipse
Nov. 28, 2012, Penumbral eclipse
Information at

14. Solar Eclipses When the Moon’s shadow covers part of the Earth
Only happens at New Moon
Three types: Annular, Partial, and Total
Diagram from Fred Espenak, may be found along with lots of good information at

15. Total Solar Eclipse
Observers in the “umbra” shadow see a total eclipse (safe to view the Sun); can see the corona
Those in “penumbra” see a partial eclipse—not safe to look directly at Sun
Only lasts a few minutes
Path of Totality about 10,000 miles long, only 100 miles wide
Diagram by Fred Espenak and more information may be found at

16. Photo of a Total Eclipse
From

17. Annular Solar Eclipse
When the Moon is too far to completely cover the Sun—the umbra doesn’t reach the Earth
Sun appears as a donut around the Moon
Diagram from Fred Espenak, may be found along with information at

18. Photos of an Annular Eclipse
From photos taken by Fred Espenak
photos taken by Fred Espenak

19. Upcoming Solar Eclipses
July 11, 2010, total solar eclipse — not visible in USA
Jan. 4, 2011, partial solar eclipse—not visible in USA
June 1, 2011, partial solar eclipse—not visible in USA
July 1, 2011, partial solar eclipse—not visible in USA
Nov. 25, 2011, partial solar eclipse—not visible in USA
Next solar eclipse in continental USA--May 20, 2012 (annular)
Next Total Solar Eclipse in continental USA—August 21, 2017
Information at

20. Tides The Moon’s gravity tugs on the Earth.
It pulls the most on the part of Earth closest, which raises the atmosphere, the oceans, and even the rocks (a little)
It pulls the least on the part of Earth that’s farthest, which allows the oceans and atmosphere to be further from the Moon (and higher)
The Sun’s gravity does the same thing, but to a lesser extent
It's not a question of mass, but of energy! The tidal force exerted by the Moon on the Earth causes the oceans to bulge. The Earth rotates about its axis faster than the Moon revolves around the Earth, and this rapid rotation carries the tidal bulge of the oceans forward of the Moon in its orbit. So the tidal bulge on the Earth is always slightly ahead of the Moon's own position. This bulge is continuously tugging the Moon forward, increasing the Moon's total energy. Imagine a cowboy's lasso. As the cowboy spins the lasso faster and faster (increasing its total energy), the loop gets wider. The same thing essentially happens to the Moon. The tugging of the Earth's bulge lifts it into a wider orbit around the Earth.

21. Tides and the Moon