Why does the Moon change shape?

Why does the Moon change shape?
Lesson narration:
English Spanish
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DISCUSS:
What do you notice about the Moon each night? (1 of 14)

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DISCUSS:
What do you notice about the Moon each night? (2 of 14)

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DISCUSS:
What do you notice about the Moon each night? (3 of 14)

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DISCUSS:
What do you notice about the Moon each night? (4 of 14)

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DISCUSS:
What do you notice about the Moon each night? (5 of 14)

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DISCUSS:
What do you notice about the Moon each night? (6 of 14)

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DISCUSS:
What do you notice about the Moon each night? (7 of 14)

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DISCUSS:
What do you notice about the Moon each night? (8 of 14)

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DISCUSS:
What do you notice about the Moon each night? (9 of 14)

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DISCUSS:
What do you notice about the Moon each night? (10 of 14)

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DISCUSS:
What do you notice about the Moon each night? (11 of 14)

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DISCUSS:
What do you notice about the Moon each night? (12 of 14)

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DISCUSS:
What do you notice about the Moon each night? (13 of 14)

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DISCUSS:
What do you notice about the Moon each night? (14 of 14)

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DISCUSS:

Before you start the activity, discuss as a class: what ideas do you plan to test to see if you can create the Moon’s phases and make them go in order?

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Check out the video in the next slide to see your Moon phase model compared side-by-side with the real sky!

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DISCUSS:

Now that you've learned what causes the Moon's phases, how would you explain it to someone who doesn't know?

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Moon


1 of 11

a large, round object in the night sky that can reflect the Sun's light
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moon phase


2 of 11

the part of the Moon that we can see on a particular night
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new moon


3 of 11

moon phase when the Moon looks completely dark
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crescent moon


4 of 11

moon phase when the Moon looks like a sliver
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half moon


5 of 11

moon phase when the Moon looks like half of a circle
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gibbous moon


6 of 11

moon phase when the Moon looks like a little less than a full circle
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full moon


7 of 11

moon phase when the Moon looks like a circle
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pattern


8 of 11

something that happens again and again and again in a way that can be predicted
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cycle


9 of 11

a set of events that repeats in the same order over and over
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orbit (revolve)


10 of 11

to circle another object, like the Moon around the Earth
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model


11 of 11

a pretend version of something that scientists use when the real thing is too big, small, or complicated to work with
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Image & Video Credits

Mystery Science respects the intellectual property rights of the owners of visual assets. We make every effort to use images and videos under appropriate licenses from the owner or by reaching out to the owner to get explicit permission. If you are the owner of a visual and believe we are using it without permission, please contact us—we will reply promptly and make things right.

Exploration
Venus & the Moon by Claude.schneider , used under CC BY-SA / cropped, adjusted color, added border
moon rising by flowcomm , used under CC BY / cropped, adjusted saturation, layered with another image
reaching for the moon by Sivaprasad k S / spliced
full moon by Krückstock , used under CC BY-SA / adjusted saturation
harvest moon rising by slworking2 , used under CC BY / adjusted color and speed
moon in daylight by Zeynel Cebeci , used under CC BY-SA / adjusted color and cropped
moon in sky by Bill Johnston / cropped, layered with other imagery
crescent gibbous moon by Thomas Bresson , used under CC BY / Heavily modified
crescent moon by P. Bramwell / Heavily modified
moon view by Luc Viatour , used under CC BY-SA / Heavily modified
house at night by StruffelProductions / cropped
sunrise background by Stellarium / Heavily modified
tablet by simon-ho / Heavily modified
lightbulb by KMJ , used under CC BY-SA / Heavily modified
Earth by Celestia / part of a diagram
Other
crescent moon by Richard Flink , used under CC BY-SA / cropped, adjusted color
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Lesson narration:
English Spanish

Activity Prep

Print Prep

This lesson explores why the Moon seems to change shape (phases) over the course of a month. In the activity, Model the Moon's Phases, students use a styrofoam ball as a model of the Moon and a flashlight as a model of the Sun to gain a better understanding of how the interactions between the Sun and Moon are responsible for the Moon’s phases.

Preview activity
Number of students:

I have a Mystery Pack

Pencil
Sharpened. Skewers also work.
Details
1 pencil per pair
Bright Flashlights
You can also use a bright lamp or overhead projector that you can point towards the students to serve as the Sun for multiple groups. Be careful not to look directly into such a bright light source.
Details
1 flashlight per pair
Styrofoam Balls (2")
We suggest smooth, solid styrofoam balls. Rough foam balls are translucent and don't work as well. You can substitute any round opaque object that can be skewered.
Details
1 ball per pair
Prep Instructions

We suggest students work in pairs. Homeschool students will need a partner for this activity.

Prepare to Darken the Room

It is important to get your room as dark as possible! It's worth taking the time to black out your windows and even tape curtains to eliminate cracks of light. Also, the brighter your flashlights, the better the demonstration. The flashlights we link to are particularly bright and inexpensive.

Exploration

13 mins

Hands-On Activity

25 mins

Wrap-Up

7 mins

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Vocabulary

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