1. Bell work
What do you think is happening in space when solar eclipses happen?

2. Eclipses
Solar Eclipses

3. Objectives for today
Describe the causes of lunar and solar eclipses.
SPI I can explain the difference between a solar and a lunar eclipse.

4. What is an eclipse?
The Sun, Earth, and Moon occasionally line up so that we have an eclipse.
These eclipses happen every year
There are two types of eclipses
Solar
Lunar
To see a solar eclipse, you need to be on a particular part of the Earth
To see a Lunar eclipse, you need to be on the night side 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.

5. What is an eclipse?
Celestial bodies are always “eclipsing” or moving in front of each other.
Eclipses occur at predictable intervals.
Other names include: Transits and Occultations.

6. What is a solar eclipse?
A solar eclipse is when the moon covers up the sun!
This occurs during the day time.
The moon moves in front of the sun.

7. 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

8. Objectives for today
Describe the causes of lunar and solar eclipses.
SPI I can explain the difference between a solar and a lunar eclipse.

9. Total solar eclipse geometry showing path of umbral shadow (or totality).

10. Total Eclipse of the Sun

11. 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

12. 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

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

14. Annular Eclipse of the Sun

15. Total Solar eclipse
Annular eclipse

16. This graphic shows the path of totality for different solar eclipses through Notice there are two solar eclipses that cross the United States (2017 and 2024).

17. Objectives for today
Describe the causes of lunar and solar eclipses.
SPI I can explain the difference between a solar and a lunar eclipse.