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Moon & Its Phases

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What you will learn from this videoWhat you will learn
- The moon’s phases are caused by its orbit around the earth.
- The moon does not make its own light, it only reflects it.
- The phases of the moon repeat in a cycle about every 28 days.
- The moon is smaller than the sun but appears the same size because it’s closer.
- Discussion Questions
Before Video
Is the moon always the same shape? ANSWERYes, the moon is always shaped like a ball; however, it looks like it is changing shape because only part of it is lit up by the sun as it orbits the earth.
The phases of the moon repeat in a cycle about once a month. It starts with new moon, then crescent, quarter, gibbous and full moon. Then the phases repeat in reverse. That whole cycle takes about 28 days.
When you compare the moon and the sun they do appear the same size to us on Earth, but in reality the sun is 400 times lager. They look the same size because the moon is 400 times closer!
The moon does not create its own light, it only reflects light from the sun.
Not that we know of. Conditions on the moon are not right to support life. We have not found any evidence of life or any fossils. There is also no water on the moon which is needed for life as we know it.
They mainly study them through telescopes. They also send different kinds of spacecraft to other planets and their moons. Humans landed on the moon for the first time about 50 years ago and we have sent spacecraft to many planets, including one currently on Mars!
After Video
What causes the moon to look like it is changing shape?ANSWERAs the moon orbits the earth, the sun always shines on half of it, but from Earth we may only see part of that illuminated surface. The phase we see depends on where the moon is in its orbit around the Earth.
The moon is lit by the sun. It is important to remember that the moon does not make its own light, it only reflects light from the sun.
The moon is smaller than the sun but it is also 400 times closer. That makes it seem like it is the same size as the sun.
Asteroids smashing into the surface of the moon created some of the features we can see on the moon’s surface (craters). Volcanic activity in the past created other features like mountain ranges and dark areas called “mares.” Volcanic activity stopped a few billion years ago, but asteroids continue to hit the moon because there is very little atmosphere to stop them.
The pull of moon’s gravity affects the water of the oceans and causes tides.
Some moons of Jupiter and Saturn have chemicals that could provide energy for living things. An atmosphere and liquids can be found on one of Saturn’s moons.
- Vocabulary
- The Moon DEFINE
The moon is a natural object that orbits around the Earth. Earth has only one moon called “the moon” but other planets like Jupiter have at least 69 moons!
- Earth-Moon-Sun System DEFINE
A system is a set of things that are connected. The earth, moon and sun are connected because their orbits depend on each other. The earth orbits around the sun and the moon orbits around the earth.
- New Moon DEFINE
The first phase of the moon. In this phase, the moon is completely dark since we can’t see the side that the sun is shining on.
- Crescent Moon DEFINE
The second phase of the moon. In this phase, we can see sunlight reflecting off only about one quarter of the moon’s surface that faces us.
- Quarter Moon DEFINE
The third phase of the moon. In this phase, we can see sunlight reflecting off half of the moon’s surface that faces us.
- Gibbous Moon DEFINE
The fourth phase of the moon. In this phase, we can see sunlight reflecting off three quarters of the moon’s surface that faces us. It’s not a full moon yet, but it’s getting there.
- Full Moon DEFINE
The fifth phase of the moon. In this phase, we can see sunlight reflecting off ALL of the moon’s surface that faces us. In this phase the moon appears round and completely lit up.
- Asteroid DEFINE
A large rocky object found flying through space. They can be just a few feet in diameter to hundreds of miles in diameter!
- Lunar Rays DEFINE
Streaks left by an asteroid hitting the moon as material is ejected due to the force of the impact. Lunar material flies out in different directions leaving trails called rays. Scientists can learn about the asteroid impacts of the past from the patterns of rays they leave behind.
- Lunar Mare DEFINE
Huge, dark areas on the moon’s surface formed by ancient volcanic eruptions.
- Tides DEFINE
The alternate rising and falling of the ocean due to the gravitational pull of the moon.
- Apollo Missions DEFINE
A series of space flights by the United States from 1961-1972 with a goal of landing a person on the moon. They succeeding in 1969 with Apollo 11.
- The Moon DEFINE
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