Chapter 4 - SpaceChapter 4 - Space

Lesson 17:Lesson 17:

Earth Movements – Rotation Earth Movements – Rotation and Revolutionand Revolution

ObjectiveObjective

The student will differentiate The student will differentiate between the Earth’s rotation and between the Earth’s rotation and revolution.revolution.

Main IdeaMain Idea

The planet Earth is constantly The planet Earth is constantly moving through space. The Earth moving through space. The Earth spins on its axis and moves spins on its axis and moves around the Sun. around the Sun.

In this lesson, you will learn more In this lesson, you will learn more about Earth’s motions. about Earth’s motions.

Earth’s RotationEarth’s Rotation

From Earth, it From Earth, it appears that the appears that the sun rises in the sun rises in the east and sets in east and sets in the west. the west.

Earth’s RotationEarth’s Rotation

This is because of This is because of Earth’s rotation, or Earth’s rotation, or spinning.spinning.

Earth spins on its Earth spins on its axis. You can axis. You can imagine the axis as imagine the axis as a pole that goes a pole that goes from the North from the North Pole to the South Pole to the South PolePole

Earth’s RotationEarth’s Rotation

Earth makes one Earth makes one complete complete rotation, from rotation, from east to west, in east to west, in 24 hours. The 24 hours. The time it takes for time it takes for Earth to spin once Earth to spin once around on its axis around on its axis is called a day.is called a day.

Earth’s RotationEarth’s Rotation

As the sun sets in As the sun sets in the west, the sun the west, the sun disappears from disappears from view in your part of view in your part of the world. As the the world. As the sky darkens, you sky darkens, you can see many other can see many other objects in the sky objects in the sky such as stars, such as stars, planets, and moons.planets, and moons.

Earth’s RevolutionEarth’s Revolution

As you know, the stars in the sky As you know, the stars in the sky make patterns called make patterns called constellations.constellations.

The stars have been in the same The stars have been in the same positions in our visible sky for positions in our visible sky for thousands of years. But not all of thousands of years. But not all of the stars are visible at the same the stars are visible at the same time.time.

Earth’s RevolutionEarth’s Revolution

If it is early spring, then you may not If it is early spring, then you may not be able to see Orion in the night sky. be able to see Orion in the night sky.

Earth’s RevolutionEarth’s Revolution

This is because of Earth’s This is because of Earth’s revolution.revolution.

Earth makes one revolution Earth makes one revolution around the sun every 365 days. around the sun every 365 days. The time to make one full The time to make one full revolution around the sun is what revolution around the sun is what we call a year on Earth.we call a year on Earth.

Earth’s RevolutionEarth’s Revolution

Earth’s RevolutionEarth’s Revolution

Different constellations and Different constellations and different parts of the night sky different parts of the night sky are visible during different parts are visible during different parts of the year. These differences of the year. These differences are what inspired the different are what inspired the different signs of the zodiac.signs of the zodiac.

Earth’s SeasonsEarth’s Seasons

In one year, Earth goes through In one year, Earth goes through four seasons. four seasons.

The seasons on Earth are due to a The seasons on Earth are due to a tilt in Earth’s axis and Earth’s tilt in Earth’s axis and Earth’s revolution around the sun.revolution around the sun.

Earth’s SeasonsEarth’s Seasons

Earth’s SeasonsEarth’s Seasons

When it is summer in North When it is summer in North America, our half of Earth is tilted America, our half of Earth is tilted toward the sun. This tilt makes toward the sun. This tilt makes the days longer and warmer than the days longer and warmer than during winter months.during winter months.

Earth’s SeasonsEarth’s Seasons

During winter, our half of Earth is During winter, our half of Earth is tilted away from the sun, making tilted away from the sun, making the days shorter and cooler. the days shorter and cooler.

When it is winter in the northern When it is winter in the northern hemisphere (half) of Earth, then it hemisphere (half) of Earth, then it is summer in the southern is summer in the southern hemisphere.hemisphere.

Earth’s SeasonsEarth’s Seasons

Earth’s SeasonsEarth’s Seasons

Which of these is a result Which of these is a result of the spinning of Earth of the spinning of Earth on its axis?on its axis? A. The apparent motion of the A. The apparent motion of the

sun in the skysun in the sky B. The motion caused by Earth’s B. The motion caused by Earth’s

revolutionrevolution C. The constellationsC. The constellations D. The change from spring to D. The change from spring to

summersummer

Which of these is a Which of these is a result of the spinning result of the spinning of Earth on its axis?of Earth on its axis?

A. The apparent motion of the A. The apparent motion of the sun in the skysun in the sky

Why are different Why are different constellations visible in constellations visible in the night sky at different the night sky at different parts of the year?parts of the year? A. Earth’s wobbleA. Earth’s wobble B. Earth’s rotationB. Earth’s rotation C. Earth’s revolutionC. Earth’s revolution D. Earth’s tidesD. Earth’s tides

Why are different Why are different constellations visible in constellations visible in the night sky at different the night sky at different parts of the year?parts of the year?

C. Earth’s revolutionC. Earth’s revolution

What causes the What causes the seasons on Earth?seasons on Earth? A. Earth’s revolution and the tilt A. Earth’s revolution and the tilt

of its axisof its axis B. Earth’s rotation and the tilt of B. Earth’s rotation and the tilt of

its axisits axis C. Earth’s rotation and wobbleC. Earth’s rotation and wobble D. Earth’s tides and rotation on D. Earth’s tides and rotation on

its axis its axis

What causes the What causes the seasons on Earth?seasons on Earth?

A. Earth’s revolution and the tilt A. Earth’s revolution and the tilt of its axisof its axis