Earth, Sun, and Moon
By: Claire Nidy
Section 1: Earth in Space
How does the earth move in space?
The Earth moves through space in two ways: revolution and rotation. Rotation is the spinning of Earth on it's axis. Rotation is also what causes day and night. The Earth rotates at 465 meters per second! Revolution is the movement of one object around another. The Earth revolves around the sun in it's orbit at 30 Kilometers per second! Together, revolution and rotation cause Earth to move in space.
What causes the cycle of seasons on Earth?
There are many reasons why the Earth has seasons. One if these reasons is how sunlight hits the Earth. For example, sunlight directly hits the equator, while sunlight is less direct closer to the north and south poles. This causes it to be warmer near the equator and colder near the poles, which helps cause seasons. Seasons are also caused by Earth's tilted axis. Because the Earth tilts, it becomes warmer in the hemisphere tilted towards the Sun. But, this tilt changes year-round. For example, the Northern Hemisphere cold in the winter and warm in the summer because the Northern Hemisphere is tilted towards the Sun in summer and away from the Sun in winter. Together, how sunlight hit the Earth and Earth's tilt create seasons.
Section 2: Gravity and Motion
What determines the strength of the force of gravity between two objects?
The strength of gravity between two objects if determined by the masses of each object. If an object has greater mass, then their gravitational pull is stronger than an object with little mass. If an object has a smaller mass, the their gravitational pull is weaker that an object with a large mass. The force of gravity on an object depends on weight. The higher the weigh of an object, the more force the object has on it. This is why astronauts can jump higher on the Moon. The Moon has a smaller mass that the Earth, so the gravitation pull is weaker, causing the astronaut to have a smaller weight. Here is a video to demonstrate what it would be like to walk on the moon. As you can see, their steps are causing them to push farther into the air than they normally would on Earth.
What two factors combine to keep the moon in orbit?
The two factors that keep the Earth in orbit are inertia and gravity. Inertia is the tendency of an object to resist a change in motion. Inertia keeps the moon moving forward in it's orbit. Gravity is the attractive force between two objects. Earth's gravitational pull keeps the moon close to the Earth and not away into space. Without the gravity of Earth, the moon would float off into space. Together, inertia and gravity keep the moon in orbit.
Section 3: Phases, Eclipses, and Tides
What causes the phases of the moon?
The phase of the moon that you can see depends on how much of the sunlit side of the moon is visible. The moon is not lit by itself, the sun lights the moon. Depending on where the moon, sun, and Earth are positioned, different phases are shown. For example, if you can see a full moon in the sky, then the entire sunlit side of the moon is facing Earth. But, if you see a new moon, then the entire sunlit side is facing away from Earth. Also, because the same side of the moon is visible to Earth and because the sun never changes it's position, the moon can achieve different stages in its cycle.
What are solar and lunar eclipses?
A solar eclipse is when the moon passes directly between the Earth and the sun, blocking sunlight from Earth. A lunar eclipse is when the Earth blocks sunlight from reaching the moon. Solar and lunar eclipses can also be total and partial eclipses. If you can see a total eclipse, then you are in the umbra, the darkest part of a shadow. If you are seeing a partial eclipse, the you are in the penumbra, the part of a shadow surrounding the darkest part.
What causes the tides?
Tides are caused by differences in how much the moon's gravity pulls on different part of the Earth. The side of Earth closest to the moon would experience high tide along with the side of the Earth the opposite of the moon. But, the two other sides of Earth are experiencing low tide. This occurs because the moon's gravitational pull pulls the ocean towards it. But, there is also high tide on the other side of Earth because Earth is being pulled towards the moon, and is leaving the water behind, causing the water in the ocean to rise. This is know as the tide cycle. Some areas have dramatic change in tides. For example, the highest high tide in the world is in Canada's Bay of Fundy. A map of this bay is below
Section 4: Earth's Moon
What features are found on the moon's surface?
There are three features found on the moon's surface. Maria, craters, and highlands. Marias are dark, flat areas on the moon's surface formed from huge ancient lava flows. The name maria comes from the Latin word for ocean. Galileo named these "maria" because he tough that they were oceans on the moon. Craters are large round pits caused by the impact of a meteoroid. Some craters are hundred of kilometer long. Highlands cover much of the earth surface and are light colored at the top, but also cast shadows along the rest of the highland.
What are some characteristics of the moon?
There are may characteristic of the moon. One of these characteristics is size and density. The moon is 3,476 kilometers in diameter, almost the distance across the United States. The moon's density is about one-eightieth the mass of Earth and it has a similar set-up as Earth if you look at the core. Another characteristic is it's temperature and atmosphere. The moon's temperature can range to 130 degrees in direct sunlight and -180 degrees at night. They vary so much because the moon has no atmosphere. Also, because the moon's gravity is so weak, gasses can escape quickly which also causes the moon to be cold. Lastly, another one of the moon's characteristics is water. The moon has no liquid water, but it does have ice at the poles.
How did the moon form
The theory of how the moon formed is quite simply. Scientists believe that a planet-sized object collided with Earth about 4.5 billion years ago to form the moon. This caused material from the outer layers of Earth to eject into orbit around Earth. Then, gravity caused the material to combine to form the moon. This is called the collision ring theory.
This Chapter's Vocab.
Go to the moon!
I am looking for people to volunteer to take a trip to the moon! You would go with fellow volunteers and collect data for science. Astronaut suits and helmets are not need, because I am collecting data on what would happens if a person is in space with no suit. Can you survive? The fee is $10,000,000,000. If you are interested, please RSVP below!