Explore the fascinating world of lunar phases in this comprehensive guide. Learn how to decipher the causes behind the Moon’s changing appearance and gain insights into the cycle of new moons. This article covers a hands-on experiment using clay models to simulate lunar phases, unveils the science behind Earthshine, and provides step-by-step instructions for creating your own lunar observation calendar. Delve into the mysteries of the night sky and enhance your understanding of lunar phenomena.
SCIENCE – When observed from Earth, the changes in the apparent shape of the Moon are known as lunar phases. A complete cycle of lunar phases takes about 29 1/2 days. These phases have been observed by ancient astronomers, but they did not understand them.
In this experiment, we will determine what causes the Moon to have different phases. We will examine the rate of daily change during the synodic month, which is the time between two consecutive new moons. We will also investigate the times of moonrise and moonset each day.
Learning Objective
To determine the cause of lunar phases known as new moons.
Materials
Clay about the size of a walnut
Work
Procedure
- Shape the clay into a ball and attach it to the end of a pencil. The clay ball represents the Moon.
- In a dark room, hold a flashlight at arm’s length and point the beam towards your face.
- Hold the model Moon halfway between you and the flashlight; position the model Moon parallel to the ball, flashlight, and slightly above them (see image).
- Observe the surface of the clay ball.
Results
The flashlight is very bright, making it difficult to see the surface of the ball.
Why?
The Moon shines because it reflects sunlight. The side of the Moon facing the Sun is always illuminated by the Sun. The side away from the Sun is always in darkness. As the Moon orbits the Earth, observers on Earth see different parts of the Moon. The visible illuminated surface of the Moon facing Earth is called a lunar phase. The Moon’s orbit is tilted at an angle of about 5° towards the ecliptic (the plane of Earth’s orbit). Thus, when viewed from Earth, the Moon usually appears to pass above or below the Sun’s disk. When the Moon is near the Sun, the side facing Earth is not illuminated. This phase is called the new moon. The new moon rises with the Sun in the east and sets with the Sun in the west.
Try a New Approach
- About one week before the new moon, the Moon has moved about one-quarter of the way around the Earth. In this position, half of the Moon’s side facing Earth is illuminated. Since this illuminated side is roughly one-quarter of the entire surface of the Moon, this phase is called the first quarter. It’s also called the first quarter because the Moon is one-quarter of the way along its orbit. Simulate this phase by holding the model Moon to your left side. Direct the flashlight beam directly onto the model.
- After about two weeks, the Moon is on the side opposite to Earth from the Sun. The side facing Earth is fully illuminated. This phase is called the full moon. Simulate the full moon by holding the model Moon behind you and shining the flashlight on it directly.
- The third quarter occurs around the beginning of the fourth week, about three-quarters of the way around the lunar orbit. The illuminated part is opposite to the illuminated part in the first quarter. Demonstrate this by holding the model Moon in your right hand and directing light from the left.
Instructions for Science Contest and Exhibition
Create a diagram showing the positions of the Earth, the Sun, and the Moon during its phases (see image). Add a Moon Data table showing the appearance of the Moon in each phase.
