Observations and results
How did the moon change as you slowly rotated? Were you able to see the familiar crescent and full moon phases?

Want to get even more specific with the moon phases? Between the new moon and first quarter, the moon is said to be a "waxing crescent". ("Waxing" is another word for getting larger.) Between the first quarter and full moon, it is said to be a "waxing gibbous". After the full moon and up to the last quarter, it is a "waning gibbous" moon. ("Waning" means getting smaller.) Any guess as to what we call it between the last quarter and new moon? (answer: a "waning crescent") What phase is the moon now where you live?

Like the sun, the moon also rises and sets each day, moving across the sky. But it is also often out during the daylight hours. (Have you ever noticed a pale moon in the sky on a clear sunny day?) During a new moon, the moon is actually rising about the same time as the sun, although you can't see it. Each day the moon comes up later, so that by the time it is a full moon, it rises about the same time the sun sets.

The moon often looks bigger as it's rising and smaller when it's high in the sky. This is an optical illusion: It looks relatively large because we are seeing it in comparison with objects on the horizon, such as buildings or trees. But this apparent size change as it travels across the sky has nothing to do with its distance from Earth, which averages about 238,866 miles (384,417 kilometers) away!

A lot of cultures have used the moon as a way to keep track of time. These systems are known as lunar calendars.

Bonus: The time for the moon to orbit Earth (27.3 days) is different from the time for the moon to go through all its phases (29.5 days). Why? Because Earth is not stationary but itself is moving around the sun! Because Earth takes about 12 months to go once around the sun, during the 27.3 days (about one month) that the moon is going around Earth, the Earth has moved about one twelfth the way around the sun. As a result, the moon has to go a little farther in its orbit to have the same appearance to us on Earth. In fact, we can estimate that this would take 27.3 + (1/12) X (27.3) = 29.5 days!

Share your orange moon observations and results! Leave a comment below or share your photos and feedback on Scientific American's Facebook page.

Cleanup
Remove the pencil from the orange (being careful with the sharp point); turn off the lamp and use caution—the lightbulb is hot.

More to explore
"Is It Just a Coincidence That the Moon's Period of Rotation and Revolution Are Identical?" from Scientific American
"Why Do the Moon and the Sun Look So Much Larger Near the Horizon?" from Scientific American
Complete Sun and Moon Data for One Day from the U.S. Naval Observatory
"The Phases of the Moon" overview from Woodlands Junior School
The Moon Book by Gail Gibbons, ages 4–8
The Moon by Seymour Simon, ages 9–12

Up next…
Washed Away: Rivers and Streams in an Instant

What you'll need
•    Large, shallow rectangular pan or tray with edges (the plastic lid of a storage container will work, too)
•    Disposable plastic water bottle
•    Scissors
•    Flour or another light powder
•    Different color powder, such as cocoa powder, to represent "topsoil"
•    Small round snacks, such as seeds, to represent "rocks"
•    Medium-sized round snacks, such as small strawberries or dried figs, to be "boulders"
•    Longer snacks, such as carrot sticks, to represent obstacles
•    Cereal boxes (or other thin objects that can be used to prop up one side of the tray)
•    Sink (or other larger container to catch any excess water runoff)

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