Eclipse: Test Your Understanding
Teacher's Guide
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How is a solar eclipse different from a lunar eclipse?
During a solar eclipse, the Moon blocks the view of the Sun as seen from Earth, whereas during a lunar
eclipse, the Moon passes through some part of the Earth's two shadows.
Describe what you would see during a total solar eclipse when the first and last Baily's beads form. Assume
a perfectly clear sky.
As the Moon barely covers the Sun, the first Baily's bead—a dot of light that is very bright in contrast to
the background of the eclipse-induced daytime darkness—forms when photospheric light from the Sun
shines through valleys on the edge of the Moon. The last Baily's bead gleams so brightly that it appears
as a jewel on a ring, with the band made of the corona. This appearance is known as the diamond-ring
effect.
Critical Thinking: A scientist observes a lunar eclipse with an umbral eclipse magnitude of 0.5. What type
of eclipse is this scientist most likely to be viewing, and why?
The scientist is viewing a partial eclipse. Partial eclipses have umbral eclipse magnitudes of less than
1.0, where 1.0 represents a total solar eclipse. The third type of lunar eclipse, a penumbral eclipse, has a
penumbral eclipse magnitude and not an umbral eclipse magnitude.
Critical Thinking: Describe what a person sees while standing in the Moon's umbra shadow during an
annular eclipse, and explain why.
A person standing in the Moon's umbra during an annular eclipse would experience night on the Moon
because the bulk of the Moon is between the person and a view of the Sun. This person would see Earth
in the Moon's nighttime sky and the Earth would have a small dark dot on it, which is the projection of
the Moon's umbra.
