Phases of the Moon

Patterns in Nature

Science began when people noticed patterns in nature. They wanted to explain those patterns.

For example, each morning the sun rises. Every evening, the sun sets and day turns into night. The next morning, the rises again and a new day begins.

Long ago people tried to explain this pattern. Latter scientists discovered that day and night are caused by Earth’s rotation.

Our planet rotates, or spins, around its axis. This axis is an imaginary line running through the center of the Earth from the North Pole to the South Pole.

The Earth makes a complete turn or rotation every 24 hours. The side of the Earth facing the sun has day. The side of Earth facing away from the sun had night.

1 rotation = 24 hours or 1 day

http://www.youtube.com/watch?v=W47Wa7onrIQ&feature=related

THE APPEARANCE OF THE MOON

If I was to track the moon every third night and draw the shape I see in the sky for a month. My pictures would look similar to this:

The different shapes are called phases of the moon. Because these changes always follow the same sequence, you can predict what will come next. Question: If waning crescent is that last event in the pattern, what phase will occur next?

A sequence is a pattern of events that always occurs in the same order. As you know, night always follows day. Then day follows night. This is an example of a sequence that occurs in nature. Can you think of another sequence in nature?

THE MOON!

WHY DOES THE MOON APPEAR TO CHANGE? Earth

The moon itself does not change, only its appearance changes.

Why, then, does it appear to us to change?

The phases of the moon are caused by two facts:

1)The moon reflects sunlight

2)The moon orbits the Earth.

The moon itself does not produce its own light. It seems bright because it

reflects light from the sun.

You can think of the sun as a light bulb. The moon acts as a mirror that

reflects light from this light bulb.

The moon orbits, or circles, the Earth every 29 ½ days.

The bright portion of the moon that we see each night

changes as the moon continues to orbit the Earth.

http://www.youtube.com/watch?v=y3Y7CXjnSvQ&feature=player_embedded http://www.brainpop.com/science/space/moonphases/

New Moon

During a “new moon”, the moon is between Earth and the

sun.

We see no portion of the moon’s lit surface.

We can only see the dark side of the moon, so the moon is

absent from the night sky or a dark circle.

Waxing Crescent• The waxing crescent comes after the New Moon

and before the First Quarter.• In this phase the moon continues to grow. • Starting on the right we see light!

• “Waxing”– Imagine the Moon being a candlestick. Every

time you dip a candle in the wax, it adds a layer and gets thicker.

First Quarter

As the moon continues to orbit around the Earth, we begin

to see a small sliver of the moon.

The sliver grows each night to a crescent.

Eventually, half the moon becomes lit up when the moon

reaches the “first quarter”, about a week after the new

moon.

Waxing Gibbous

Waxing Gibbous is after the

First Quarter and before

the Full Moon!

Waxing= GrowingTHINK

Light to the Right!

It takes about another week to become a full moon.

At a full moon, the earth, moon, and sun are in line.

Since the moon is on the side of the Earth opposite from

the sun, the entire sunlit part of the moon is facing us.

The dark side of the moon is entirely hidden from view.

Full Moon

This bright circle is called the

“full moon”.

Waning Gibbous

Waning Gibbous is after the

Full Moon and before the

Third Quarter

Waning= To get smaller

Third Quarter

Now the appearance of the moon starts shrinking again as it continues on its orbit. Only half the moon seems lit up in the “third quarter.”

Waning Crescent

Waning Crescent is after the Third

Quarter! It is the last phase in the sequence!

Just like the days of the week and the Water Cycle!

The moon will becomes completely dark again as a “new moon.”

Question: If the sequence is starting over again, what phase will the moon be in after the New Moon?

See next slide for questions…

Question Time!!!!• Look at the Moon Phase Calendar Based on this December 2011 Calendar…..

1. On December 18 2011, what phase was the moon?• Last Quarter

2. On December 2, 2011, what phase was the moon?• First Quarter

3. What day was the phase of the moon a New Moon?• December 24th

4. What day was the phase of the moon a Full Moon?• December 10th

5. If it is in its last quarter phase, then where was the moon located as it was orbiting?

Tell Me What You Know!• How many phases does the moon have?• What does the moon orbit around?• How long does it take the Moon to a complete

rotation? • What two phases are aligned with the Sun and

Earth? (draw the phase or write the name)• What does it mean when the moon is in its waxing

phase?• What does it mean when the moon is in its waning

phase?• Why are we able to see the moon?

Tell me what you know continued…

• Draw the Sun and Earth– If you look into the night sky and see a Full Moon,

predict where the moon will be located as it is orbiting.

– Adding to you picture, draw where the following phases would be located…

• New Moon• Third Quarter• First Quarter

Phases of the Moon Notes…The moon orbits the Earth every 29 ½ days.

The moon appears to change its shape because the moon

reflects sunlight

– The moon revolves around the Earth.

Phases of the Moon. As it orbits, we see different portions of

the moon reflecting the sun’s light.

Common phases of the moon include:

– New Moon

– First Quarter

– Full Moon

– Third Quarter

Additional Websites

• http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/moonlight.html

http://www.lpi.usra.edu/education/skytellers/moon_phases/index.shtml