Moon

Phases or

the Lunar

Cycle

TEK 8.7B Demonstrate and predict the

sequence of events in the lunar cycle

This lesson takes 3 steps

⚫ Step 1 – go over class notes as a whole

class

⚫ Step 2 – go through the learning stations in

the classroom (need to get textbook and the

tray for the supplies and instructions)

⚫ Step 3 – Explore – answer questions based

on website link – Unit 4.1, Lesson 4: “Moon

Phases”. The link is called “star date”

Step 1

Whole class notes

Moon Phases

⚫ The phase of the moon you

see depends on how much

of the sunlit side of the

moon faces Earth

The Moon

⚫ The moon is the Earth’s closest neighbor in

space. On average the moon is 384, 400 kilometers

from Earth.

⚫ It is about ¼ the size of Earth, which means

that the gravity on the moon is also about ¼ of

Earth’s

The Moon’s Orbit

⚫ The moon revolves around the Earth and rotates on its own axis

⚫ Revolution – Moon orbits the Earth every 27.3 days

⚫ Rotation – Moon turns on its axis approximately every 27 days

⚫ Therefore, The same side of the moon always faces Earth

A Day (and year) on the Moon

⚫ Because the moon revolves around the

Earth at the same rate that it rotates on its

axis, the moon’s day and year are the

almost the same amount of time!

⚫ How does a day = a year???

Moon Day/Year Comparison:

Day⚫ Definition of a day: Rotate

once on an axis

⚫ Earth rotates once = 1

day (24 hours)

⚫ Moon rotates once = 27

earth days

Year⚫ Definition of revolve:

Move around another

body

⚫ Earth takes 1 year to

revolve around the sun

(365 days)

⚫ Moon takes about 27

(earth) days to revolve

around earth

So, a moon’s day almost equals a moon’s

year!

Why one side faces Earth:

Moon’s Rotation and Revolution

Video #2 (Animation)

⚫ https://www.youtube.com/watch?v=jgoIP90apEs

Phases of the Moon

Near Side of the Moon

You see this all of the time!

Phases of the Moon

Far Side of the Moon

You never see this !

Misconception:

Dark Side of the Moon

⚫ The “Dark Side” of the Moon should really

be called the “Far Side.”

⚫ The far side gets just as much light as the

near side. We just don’t ever see it, so

people previously thought that it was dark!

Moon Phases

⚫ Moonlight is reflected

sunlight

⚫ Half the moon’s surface is

always reflecting light

⚫ From Earth we see

different amounts of the

Moon’s lit surface

⚫ The amount seen is

called a “phase”

FULL

QUARTER

CRESCENT

GIBBOUS

4 Main Shapes to the Phases

Shade in

and label!

Moon Positions = Phases

⚫ Where the moon is located in its revolution

path gives us the phases. It simply repeats

the pattern of going through these four

main shapes

Shapes and Phases

⚫ The four main shapes and the “in-

between” steps are what we call the

phases.

⚫ Let’s take a look at them now.

Moon Phases – label and shade:

New Moon Waxing

Crescent

Waning

Crescent

Waxing

Gibbous

Waning

Gibbous

1st Quarter

3rd QuarterFull Moon

When you look at the actual

moon (not shapes)…

⚫ Can you tell the difference between the

first and second one?

They are actually different

phases.

⚫ The moon is actually in a different place in

it’s revolution – Hence, it is a different

phase

⚫As the moon grows “larger”,

towards becoming a full moon,

it is called a waxing moon.

Words to Know

⚫ Waxing – To increase in size

⚫As the moon grows smaller,

away from being a full moon, it

is called a waning moon.

Words to Know

⚫ Waning – Decrease in size

Identifying Moon Phases – Tips!The shadow on the moon always disappears from right

to left when the moon is growing. If you can see the right

side of the moon, then it is growing.

The moon always disappears from left to right as well.

So if you can see the left side then it is getting smaller.

Crescent Moons are when it’s less than half illuminated,

and gibbous when it’s more than half.

Last Tip!

⚫ Determining Moon Phases in Northern

Hemisphere…

⚫ During the first quarter, the moon will look like a D.

When it’s full, it will look like an O. And when it’s in

the third quarter, it will look like a C.

Cyclical Phases of the Moon

⚫ The moon goes through its whole set of

phases each time it revolves around the

Earth.

⚫ As the moon revolves around the Earth,

you see more and more of the lighted side

of the moon.

Moon Phases Animation

Earth, Moon and Sun

Start here!

Moon Rise

⚫ The moon doesn’t always rise and set at

the same time, but changes depending on

what phase it’s in.

⚫ You can’t see a new moon because it isn’t

illuminated by the sun, and because it

rises and sets at the same time as the

sun.

Moon Rise

⚫ As the waxing moon moves into its first

quarter, it will rise in the morning, reach its

height around dusk, and set around

midnight.

⚫ Full moons come up when the sun goes

down and set when the sun comes up.

⚫ As the waning moon moves into its third

quarter, it will rise at midnight and set in

the morning.

Beautiful moon rise

Compare the top and bottom diagrams:

So What causes Phases?

⚫ Caused by changes in the relative position

of the moon, Earth, and the sun.

Step 2 – Learning Stations

⚫ Go through the learning stations to apply

your knowledge.

⚫ All of the stations are at each spot

⚫ 4 “stations” –

⚫ Read and Respond

⚫ Science Diagram

⚫ Predictions

⚫ Modeling

Step 3 - Exploration

⚫ Use the Star Date link posted on this

lesson on teacher’s website.