3rd Grade Science Fair 2025

Why Does the Moon Change Shape?

A science project by Max Jaeger, Age 9

Explore the Project
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Meet the Scientist
Max in his NASA astronaut suit at the science fair
Future Astronaut

Hi, I'm Max!

I'm 9 years old and in 3rd grade. I love space, building things, and figuring out how stuff works.

When I looked up at the sky one night and saw the Moon was only a tiny sliver, I got curious. Where did the rest of it go? That question turned into this whole science project!

I spent weeks reading, building a model, and doing experiments to find out the truth about moon phases. Spoiler: the Moon doesn't actually change shape.

Space Lover Builder 3rd Grader Moon Expert
The Project

What Is This All About?

Science Question

Does the Moon actually change its shape, or does it just look different from Earth depending on where it is in its orbit around us?

My Hypothesis

I think the Moon does not change shape. I think the Sun lights up different parts of the Moon as it travels around Earth, and that's what makes it look different to us.

My Experiment

I built a physical model using a lamp (the Sun), a ball (the Moon), and my head (Earth) to see how light falls on the Moon differently as it moves around.

My Result

My hypothesis was correct! The Moon's shape never changes. Only the lit-up part that we can see from Earth changes as the Moon orbits us.

Materials I Used

  • A bright lamp or flashlight (this was the Sun)
  • A white foam ball on a stick (this was the Moon)
  • My own head (this was Earth, I stood in the middle)
  • Ruler, tape, and a dark room
  • Science notebook for recording observations
  • Styrofoam, paint, and cardboard for the display model
Moon Science

The 8 Phases of the Moon

As the Moon travels around Earth each month, we see different amounts of the lit side. These are called moon phases. Click or tap a phase to learn more!

Select a Phase

Tap any moon around Earth to learn about that phase!

The Experiment

How My Model Works

I used a lamp and a ball to show how the Sun lights up the Moon. Here's the setup!

Lamp (Sun)
Me (Earth)
New Moon
New Moon

When the Moon is between Earth and the Sun, the lit side faces away from us. We can't see it. This is the New Moon!

1

Set Up the Sun

Put the lamp in a dark room. This lamp acts just like our real Sun sending light across space.

2

Be the Earth

Stand in the middle, facing the lamp. Your eyes are Earth, watching the Moon from the center of its orbit.

3

Move the Moon

Hold the foam ball up and slowly turn around in a circle. Watch how the light on the ball changes, just like real moon phases!

4

Record Everything

Draw what the moon looks like at 8 different spots around the circle. Compare with real moon phase photos.

Behind the Scenes

How Max Built It

It took a lot of planning, building, and a tiny bit of mess. Here's how the project came together!

Week 1
Max researching the Moon

Doing the Research

I went to the library and found books about the Moon and space. I also watched videos online about moon phases and took notes in my science notebook.

Week 2
Max building the Moon model

Building the Model

I painted a big foam ball to look like the Moon, with craters and everything. Then I put it on a stick so I could hold it up and move it around.

Week 3
Max building the Moon model

Running the Experiment

In my darkened bedroom, I set up the lamp and went through all 8 positions. I drew pictures of what I saw at each spot and labeled them.

Week 4
Max building the Moon model

Making the Display

I designed and decorated my science fair board. I printed photos of real moon phases and compared them to my drawings. They matched!

Why the Moon Matters Today

The Artemis II Mission

Right now in 2025, NASA is getting ready for the Artemis II mission, the first time humans will fly around the Moon since 1972! Four astronauts will orbit the Moon and come back safely, testing everything we need for future missions that will actually land on the Moon.

Scientists are using moon phase data, lunar maps, and everything we know about the Moon's orbit to plan the mission safely. That's why understanding moon phases isn't just a school project. It's real rocket science!

Learn more at NASA.gov
Did You Know?

Cool Moon Facts

The Moon is full of surprises. Here are some of my favorites that I discovered during my research!

Wrapping It All Up

What Max Learned

My Conclusion

My hypothesis was correct! The Moon does NOT change its shape. It is always a sphere, just like Earth. What changes is how much of the lit-up part we can see from Earth as the Moon travels around us each month.

It takes the Moon about 29.5 days to go through all 8 phases and get back to where it started. That's almost exactly one month! In fact, that's where the word "month" comes from.

What Surprised Me Most

I was really surprised that the Moon is actually always half lit by the Sun. We just can't always see the lit half from Earth. It was also cool to learn that the same side of the Moon always faces Earth. We never see the far side from the ground!

What I Would Do Next

If I do this experiment again, I would track the real Moon in the sky every night for a whole month and write down what phase it was in. I'd also love to learn more about how the Moon causes tides in the ocean!

Hypothesis:

SUPPORTED!

The Moon doesn't change shape. Only our view of its lit side changes.

Photo: Max at the science fair!
Replace with sciencefair-max.jpg

Thank you for visiting my project! I hope you learned something cool about the Moon.

Max, Age 9