The Solar System and Gravity and Weightlessness in Space

 

LESSON – THE SOLAR SYSTEM 

TOPIC
  • Introduction
  • Natural Bodies in the Sky
  • The Relationship between the Earth, Sun, Moon and the Stars
  • Earth’s Movement and their Effects
  • The Eclipse of the Sun and the Moon
  • Relationship between the Earth and Other Planetary Bodies
  • Gravity and Weightlessness in Space
  • Lesson Evaluation

 

INTRODUCTION

The solar system comprises of the sun and the nine (9) planets that move around it. Namely –

1. Mercury

2. Venus

3.. Earth

4. Mars

5. Jupiter

6. Saturn

7. Uranus

8. Neptune

9. Pluto

 

NATURAL BODIES IN THE SKY

The sky is the space above the earth, the components of the sky are:

1. The cloud

2. The sun

3. The moon

4. The star

 

THE EARTH, SUN, MOON AND THE STARS

THE EARTH 

Earth, our home, is the third planet from the sun.

Earth is the only planet known to have an atmosphere containing free oxygen, oceans of liquid water on its surface, and, of course, life.

The earth is the third planet and the only that living things are found.

The sun, moon and the star are the major natural source of light to the earth.

 

THE SUN 

The sun is the biggest object in the solar system that is give light to the earth.

It is the main source of natural light and heat on earth.

The sun is at centre of the solar system.

The movement of the sun is false (not true) and this movement is called Apparent Movement of the Sun because the sun does not move.

Apparent movement of the sun is caused by the rotation of the Earth about its axis.

 

THE MOON 

The moon is the only natural satellite on earth.

There are many moon in the solar system and the earth has one of them that shines bright in the night sky.

 

THE STARS 

The stars also produce light just the sun and the moon that shine on earth in the night sky.

The light is called self luminous.

 

THE EARTH’S MOVEMENT 

Rotation and revolution are the two types of earth’s movements with the sun at the center of the solar system as the major source of all life and energy here on earth.

 

ROTATION OF THE EARTH

Rotation can be defined as the movement of Earth around its own axis in every 24 hours.

It takes the earth 24 hours to complete a rotation around its axis.

 

EFFECTS OF EARTH’S ROTATION 

1. It causes day and night.

2. It causes time difference.

3. It causes the direction of winds.

4. It causes ocean currents to be deflected.

5. It caused apparent movement of the sun.

 

REVOLUTION OF THE EARTH

Revolution of the earth can be defined as the movement around the sun in every 365 days (or a leap year – 366 days) making one years.

It takes the earth 365 day (a year) to complete its movement around the sun.

 

EFFECTS OF THE EARTH’S REVOLUTION 

1. It causes different season. For example, the rainy (summer) and dry (winter) season.

2. It causes variation in the length of day and night.

3. It causes eclipse of the sun.

 

THE ECLIPSE OF THE SUN AND THE MOON 

The eclipse is the complete or partial darkness on the face of the earth.

At this time, the earth is unable to receive light from the sun as a result of the moon (solar eclipse) coming in between the sun and earth or the earth (lunar eclipse) comes between the sun and the moon.

There are types of eclipse,

1. Solar eclipse

2. Lunar eclipse

 

1. SOLAR ECLIPSE

Solar eclipse is known as eclipse of the sun.

The eclipse of the sun is when the moon comes in between the sun and the earth.

 

2. LUNAR ECLIPSE

Lunar eclipse is also known the eclipse of the moon.

The eclipse of the moon is when the earth comes in between the the sun and the moon.

 

RELATIONSHIP BETWEEN THE EARTH AND THE PLANETARY BODIES

THE EARTH 

The world we live in is called the earth.

Scientist discovered that it is spherical like an orange.

The earth is divided into three parts:

 

THE ATMOSPHERE (THE SKY)

It made up of gasses that envelope or surround the the planet earth.

The cloud, the stars, the moon and the sun are found in the atmosphere.

The rainfall, thunder and lightening occur there.

The air we breath in and out is part of the atmosphere.

 

THE HYDROSPHERE (THE WATER)

It is the part of the earth covered by water. Hydrosphere includes streams, rivers, lakes, lagoons, seas and oceans. Hydrosphere covers 70% of the total earth’s surface.

 

THE LITHOSPHERE (THE LAND)

It is the solid part of the earth where soil, rocks, plants and animals are found.

 

THE SUN 

The Sun is at the center of the solar system. It is a larger star and the main source of energy on the earth.

 

THE MOON – the moon is the earth only natural satellite. Just like the sun, it is round and gives light to the earth at night through the reflection of the sun.

 

THE STARS – Just like the sun, the stars produced light by themselves like the sun and also give light to the earth at night.

 

THE CLOUD 

It is a great mass of matter which contain tiny drops of water. It is usually while or grey in colour.

 

GRAVITY AND WEIGHTLESSNESS IN SPACE

Have you discovered that whatever you throw up comes back to the ground?

What responsible for this?

That’s called gravity or gravitational force.

Gravity is the force that draws any objects toward its center.

It is also called attractive force that keeps you on the ground.

The force keeps all of the planets in orbit around the sun.

 

THE FORCE OF GRAVITY 

There is a force in the centre of the earth that attracts things to the surface of the earth in the same way that magnets attract some metals.

 

Without the force of gravity, we will not be able to walk upright.

If we jump up we will not be able to come back to the earth.

We will just float about like a very light paper.

 

LESSON EVALUATION 

Answer all the questions in Section A and B.

SECTION A 

1. describe the relationship between the earth, sun, moon and the star.

2. explain the meaning of earth movement.

3. state types of earth’s movement.

4. state the relationships and the difference between earth’s rotation and revolution.

5. mention 3 effects of earth’s rotation.

6. state 3 effects of the revolution of the earth.

7. differentiate between the solar and lunar eclipses.

 

SECTION B

Complete the following statements,

8. The earth and the moon get their light from the _________.

9. _________, _________ and _________ are the source of light energy on earth.

10. The earth completes its rotation in _________ and revolution in _________.

11. The path followed by the earth round the sun is known as _________.

12. Day and night is caused by _________.

13. Eclipse of the sun and the mood are known as _________ and _________.

14. When the earth comes in between the sun and moon, it is called _________.

15. When the moon comes in between the sun and the earth, it is known as _________.

16. state some relationships among the earth, planets, stars, sun, and moon.

 

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