Shadows and Eclipses
Both the Earth and the Moon will cast shadows.  If the Sun, Earth, and Moon are all lined up, then the shadow from one can fall on the other.
Because the Earth is ~4 times bigger, it will cast a shadow 4 times bigger.
Umbra Portion of shadow where it is completely dark.
(for a person in the shadow, the light bulb would be completely blocked out)
Penumbra Portion of shadow where it is only partially dark.
(for a person in the shadow, the light bulb would be partially blocked out)
(To remember the names, think of “ultimate” and “penultimate”)
From our text:  Horizons, by Seeds