Earth's Motions
What is a lunar eclipse?
KEY TERM
lunar eclipse: passing of the moon through the Earth's shadow
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What is a lunar eclipse?
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As you know, the moon does not give off its own light. The moon gets
its light from the sun. The light then reflects onto the Earth.
The moon revolves around the Earth. Most of the time the moon does
not move into the Earth's shadow. But sometimes it does. Since the Earth
is much bigger than the moon, the Earth has a much bigger shadow. The
moon can fit in this shadow. When the moon moves into the Earth's
shadow, we have a lunar eclipse.
During a lunar eclipse, hardly any sunlight reaches the moon. The moon
becomes very dim.
You may ask, "How does the moon receive any sunlight when it is
hidden in the Earth's shadow?" The answer is that the Earth's air
"bends" some of the sun's light onto the moon. So, even when the moon
is eclipsed, it is not completely blacked out. It just looks dull red.
A lunar eclipse lasts much longer than a solar eclipse. This is because the
Earth's shadow is very wide where the moon passes. The moon takes a
long time to pass through.
From start to finish, a lunar eclipse lasts from three to four hours and
sometimes longer.
A lunar eclipse can be seen from more areas of the Earth than a solar
eclipse. During a solar eclipse, the moon's shadow covers only a small
part of the Earth. A solar eclipse can be seen only on a small part of the
Earth. A lunar eclipse is different. During a lunar eclipse, the entire moon
is in shadow. It can be seen from any part of the Earth that is having
night at the time of the eclipse.
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UNDERSTANDING A LUNAR ECLIPSE
Figure A shows a total lunar eclipse. Study it. Then fill in the blanks.
Identify the following by letter:
1. Sun
2. Earth
3. Moon
4. Moon's orbit
5. Earth's umbra
6. Earth's penumbra
Figure A During a lunar eclipse, the sun,
Earth and moon line up in a straight line
with the Earth in the middle.
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There are two kinds of lunar eclipses: total and partial.
The moon looks like this when it is not eclipsed:
A total lunar eclipse looks like this:
A partial lunar eclipse may look like any of these:
7. The moon is in total eclipse when it is in the Earth's
umbra, penumbra
8. The moon is in partial eclipse when it is in the Earth's
umbra, penumbra
9. When the moon is only partly in the Earth's penumbra, the eclipse is
total, partial
10. When the moon is partly in the umbra and partly in the penumbra, the eclipse is
total, partial
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THE MOON'S POSITION DURING AN ECLIPSE
Figure B shows the moon in five different positions. What does it look like in each position?
Match the positions with the "moons" below.
Figure B
Figure C
Figure D
Figure E
Answer by letter.
1. In position 1, the moon looks like
2. In position 2, the moon looks like
3. In position 3, the moon looks like
4. In position 4, the moon looks like
5. In position 5, the moon looks like
Now answer by number.
6. At which position is the moon not eclipsed at all?
7. Why is it not eclipsed?
8. At which position is the moon totally eclipsed?
9. At which positions is the moon partially eclipsed?
10. Which one is partially eclipsed the most?
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Figure F
Figure G
TRUE OR FALSE
In the space provided, write "true" if the sentence is true. Write "false" if the sentence is false.
I. The moon makes its own light.
2. The moon reflects the sun's light.
3. Dpiing a lunar eclipse, the moon is in the Earth's shadow.
4. During a lunar eclipse, part of the Earth is in the moon's shadow.
5. During a solar eclipse, part of the Earth is in the moon's shadow.
6. During a solar eclipse, the moon is in the Earth's shadow.
7. The whole moon can be covered by the Earth 's shadow.
8. The whole Earth can be covered by the moon's shadow.
9. The darker part of a shadow is the umbra.
10. the darker part of a shadow is the penumbra.
MATCH ING,
Match each term in Column A with its description in Column B. Write the correct letter in the
space provided.
Column A
Column B
1. umbra
a) light part of a shadow
2. solar eclipse
b) moon is in the Earth's shadow
3. lunar eclipse
c) reflects the sun's light
4. penumbra
d) darker part of a shadow
5. moon
e) part of the Earth is in the moon's
shadow
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FYLL THE BLANK
Complete each statement using a term or terms from the list below. Write your answers in the
spaces provided. Some words may be used more than once.
moon
Earth's atmosphere
predict
reflects
Earth
larger
disappear
night
dull red
does not
longer
sun
make its own light. The moon
1. The moon
the sun's light.
2. During a lunar eclipse, the moon passes through the shadow of the
is between the
3. During a lunar eclipse, the
and the
4. During a total lunar eclipse, the moon does not completely
5. A "totally" eclipsed moon is not completely blacked out because the
bends some light onto it.
6. An eclipsed moon looks
7. The Earth's shadow is much
8. A lunar eclipse lasts
than the moon.
than a solar eclipse.
9. When a lunar eclipse is taking place, it can be seen from any part of the Earth that
is having
10. Scientists can
when and where eclipses will take place.
REACHING OUT
A lunar eclipse can take place only during one moon phase. Which phase is it? Why?
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