1. Eclipses

2. Shadows
Umbra - the darker part of a shadow where all the light is blocked
Penumbra - a partial shadow
These terms also apply to Solar Eclipses and Lunar Eclipses.

3. Solar Eclipse
Umbra
Sun
Full Shadow
Earth
Moon
Partial Shadow
Penumbra
A solar eclipse occurs when the Moon passes in front of the Sun.

4. Lunar Eclipse
Sun
Earth
Moon
A lunar eclipse occurs when the Moon passes into the Earth's shadow.

5. Questions
Which type of eclipse is dangerous to view with the unprotected eye?
Why are lunar eclipses more commonly seen than solar eclipses? *

6. You will observe a total eclipse of the sun when...
(a) you stand in the penumbra of the moon’s shadow
(b) you stand in the umbra of the moon’s shadow
(c) sunlight diffracts around the moon
(d) sunlight reflects from the moon to the earth
(b) you stand in the umbra of the moon’s shadow