1. Eclipses

2. Bell Work
Try the phases of the moon exam question

4. Learning Outcomes
• To distinguish between lunar and solar eclipses and describe their mechanisms.
• To describe the appearance of the Sun and Moon during solar and lunar eclipses.
• To appreciate that eclipses do not occur every time the phase of the Moon is either full or new.

5. What is the definition of an eclipse?
An eclipse is when the shadow of a celestial body, such as the Earth or Moon, obscures the light of another object in space.

6. Types of Lunar Eclipse There are two main types of eclipse:
•A solar eclipse when the Sun is obscured by the Moon
•A lunar eclipse where the Moon is obscured by the Earth's shadow

7. Types of Solar Eclipse There are four types of solar eclipse
•Total solar eclipse
•Partial solar eclipse
•Annular eclipse
(we will come back to
this later)
Key words
Apogee – Furthest point
Perigee – Closest point
Umbra – Full Shadow
Penumbra – Partial Shadow
Syzygy – Allignment
Nodes – Where the moon's orbit intersects the ecliptic

8. What happens during a solar eclipse?
During a solar eclipse the Moon blocks the Sun’s rays from reaching part of the Earth.
During a solar eclipse the Moon moves directly between the Sun and the Earth.
Where must the Moon be for a solar eclipse to take place?

9. Always use eclipse viewers, NEVER look directly at the sun.
The Earth

10. What happens during a lunar eclipse?
During a lunar eclipse the Earth blocks the Sun’s light
from reaching the Moon.
During a lunar eclipse the Moon is on the opposite side of
the Earth to the Sun.
Where must the Moon be for a lunar eclipse to take place?

11. What happens during an annular eclipse
Because of the varying distance, the Moon appears larger when it is at perigee (close).
Although it is much smaller than the Sun, the Moon's apparent size then roughly matches the Sun's, as seen from Earth. For that reason, it can only cover all of the Sun's disk during a solar eclipse when it is at perigee.
On the other hand, when the Moon is at apogee, its apparent size is so small that the Sun's outer edges are still visible and an annular solar eclipse can be observed.

12. Want to know more about perigee and apogee?

13. Mini Review
Draw a diagram of a lunar, and solar eclipse including ray diagrams.

15. Construct Your Knowledge
Why do we not have an eclipse every lunar orbit? Produce a word document explaining this with a diagram.

16. Duration of Eclipses
The length of a solar eclipse depends on where the Moon's shadow falls on the Earth's surface and where the observer is on that shadow. During a solar eclipse the maximum possible duration of totality is 7 minutes 31 seconds.

17. Mini Review

18. Construct Your Knowledge
Find out what eclipses mean to different civilisations. It might be an idea to look at Ancient Greek, Chinese, Native American etc.

19. Word Pad Review