Eclipses

WHAT ARE
ECLIPSES?

Lesson 3
Unit 4 The Sun-Earth-Moon System

Encountering the Phenomenon

What do you think is causing these bites out of the

Sun?

WHAT IS

A SHADOW?

01

SHADOWS

●The umbra is the central, darker part of the shadow where light is
totally blocked.

●The penumbra is the lighter part of a shadow where light is partially
blocked.

Umbra and penumbra in spanish: umbra y penumbra

Multiple Choice

Which part is the umbra?

• A

• B

Understanding these parts of
shadows will help us
understand eclipses.

Multiple Choice

The penumbra is the

• center of a shadow

• completely dark area of a shadow

• partially shaded outer region of a shadow

• fully illuminated inner region of a shadow

WHAT IS

AN ECLIPSE?

02

ECLIPSES

●An eclipse occurs when an
astronomical object comes between
two other astronomical objects.

●There are times when the Earth is
between the Sun and the Moon.

●Other times the Moon is between the
Earth and the Sun.

Earth

Sun

Moon

Earth

Sun

Moon

SOLAR

ECLIPSES

03

SOLAR ECLIPSE

●Occurs only when there is a new moon

●The Moon is positioned between the Earth and the Sun

●The Moon hides all or part of the Sun's light, casting a shadow on
Earth

●Solar eclipses can be of several types

Multiple Choice

True or false: This is an eclipse.

• True

• False

Draw a diagram of a solar eclipse

TOTAL SOLAR ECLIPSE

●Occurs when the Moon hides all the light from the Sun

●

The umbra is much narrower than the penumbra

●It looks like night time in the middle of the day

●

If you are outside of the umbra and penumbra, you cannot
see the ellipse at all.

What it’s like to watch a Total
Solar Eclipse

Why people get so excited about
a total solar eclipse

PARTIAL SOLAR ECLIPSE

●If you are in the moon’s penumbra, you will see a partial eclipse.

●Occurs when the Moon comes between the Sun and the Earth, but
not completely

●Part of the Sun is visible

●The day is darkened just a little bit and the Sun looks like a
cookie with a bite

Multiple Select

What can you expect to see during a solar eclipse?

• The moon passing between the sun and Earth, partially or fully blocking the sun's light.
• Day becoming night

• Wolves turning into werewolves

• Stars in the dark sky

Multiple Choice

Based on this image, people in the west coast are able to experience night becoming day.

• True

• False

Multiple Choice

What kind of eclipse will you see when you are in the penumbra?

• annular eclipse
• total eclipse
• partial eclipse
• lunar eclipse

Solar Eclipse 101

What is a Solar Eclipse?

LUNAR

ECLIPSES

04

LUNAR ECLIPSE

●Occur when the Earth is placed between the Moon and the Sun, during
a full moon.

●The moon is in the Earth’s shadow; the sun's rays are blocked from
reaching the Moon

●Occurs frequently, can be seen from any part of the Earth where it is
nighttime.

●They last several hours.

●The most frequent are partial lunar eclipses and total lunar eclipses.

Multiple Choice

What is the correct order during a lunar eclipse?

• Sun, Earth, Moon
• Sun, Moon, Earth
• Moon, Earth, Sun
• Earth, Sun, Moon

Multiple Choice

True or False: Only people in the moon's path of totality can see the lunar eclipse.

• False
• True

Lunar Eclipse 101

TOTAL LUNAR ECLIPSE

●Occurs when the entire Moon moves through Earth’s umbra

●

The Moon is visible when it is completely in Earth’s umbra.

Multiple Choice

Where does the moon need to be in order for us to see a total lunar eclipse?

• In the Earth's atmosphere
• In the sun's umbra

• In the Earth's umbra

• Outside the Earth's umbra

Why does the moon appear red?

Why does the moon appear red?

●Earth blocks most of the Sun’s rays.

●Some rays deflect off Earth’s atmosphere and into Earth’s
umbra.

●This reflected sunlight has a reddish color and gives the Moon a
reddish tint during a total lunar eclipse.

●This is also why you can see the unlit part of the Moon on a clear
night.

●Astronomers often call this Earthshine.

Multiple Choice

What is Earthshine?

• Bright illumination of the dark side of the Moon by sunlight reflected from Mars.
• The glow of the Earth's atmosphere during a meteor shower.
• Faint illumination of the dark side of the Moon by sunlight reflected from the Earth's surface.
• The reflection of city lights on the Moon's surface.

Multiple Choice

Why does the moon appear red during a lunar eclipse?

• due to the reflected sunlight

• because of a change in its composition

• due to the reflected red light from Mars

• due to a chemical reaction with Earth's atmosphere

Partial LUNAR ECLIPSE

●Occurs when only part of the Moon passes through Earth’s
umbra, the Moon is never completely covered by Earth’s
umbra.

●

The part of the
Moon in Earth’s
umbra appears
much darker.

●

The part of the
Moon in Earth’s
penumbra
darkens slightly.

HOW OFTEN DOES

AN ECLIPSE OCCUR?

05

Why aren’t there eclipses every month?

If a solar eclipse can only occurs during the new moon phase and a
new moon occurs about every 29.5 days, why don’t we see a solar
eclipse every month?

●Certain conditions must be met for a total solar eclipse or a
total lunar eclipse to occur.

Rare Eclipses

●Solar eclipses do not occur at every new moon phase.

●The Moon’s orbit is slightly tilted compared to Earth’s orbit.

● During most new moons, Earth is above or below the Moon’s
shadow.

●Lunar eclipses also do not occur every month.

●During most full moons, the Moon is slightly above or slightly
below Earth’s penumbra.

●Eclipses only occur when the sun, earth, and moon are in syzygy

Multiple Choice

Why don't we see an eclipse every month?

• The Moon's orbit is a perfect circle
• Eclipses are a rare phenomenon
• The Earth's rotation speed is not consistent
• The Moon's orbit is tilted relative to Earth's orbit around the Sun.

230
ECLIPSES

Throughout this century there will be 223 solar eclipses.
Likewise, there will be 230 lunar eclipses.

Weird Things Animals Do During Eclipses

Eclipses Used To Be Terrifying