Basic Science and Technology – Primary 6 Weekly Short Class Lesson Notes for Second Term

WEEK 5 – THE SOLAR SYSTEM – NATURAL BODIES IN THE SKY | GRAVITY AND WEIGHTLESSNESS IN THE SPACE

THE SOLAR SYSTEM

The Solar System is made up of the Sun and all the objects that move around it. These objects include planets, moons, asteroids, comets, and meteoroids.

The Sun is at the center of the Solar System and provides light and heat to all planets.

1. The Sun – The Sun is a star. It is the largest object in the Solar System. It is also provides light, heat, and energy needed for life on Earth.

2. Planets – Planets are large objects that revolve around the Sun. They are divided into:

• Inner Planets (Rocky Planets) – Mercury, Venus, Earth, Mars. They are small and made of rock.

• Outer Planets (Gas Giants) – Jupiter, Saturn, Uranus, Neptune. They are large and made mostly of gas.

3. Moons – Many planets have natural satellites called moons. For example, Earth has one moon, Jupiter has many moons.

4. Other Objects 

• Asteroids – small rocky objects mostly found between Mars and Jupiter.

• Comets – icy bodies with tails that glow when near the Sun.

• Meteoroids – small rocks that sometimes enter Earth’s atmosphere as meteors (shooting stars).

5. Movements in the Solar System

• Planets revolve around the Sun → causes years.

• Planets rotate on their axis → causes day and night.

• Moons revolve around their planets → cause moon phases and tides.

Summary – The Solar System is made up of the Sun and all the objects that move around it, including planets, moons, asteroids, and comets.

 

THE 9 PLANETS OF THE SOLAR SYSTEM

The planets are large objects that revolve around the Sun. They are arranged in order of distance from the Sun:

1. Mercury is the smallest planet and closest to the Sun.

2. Venus is bright, hot planet with thick clouds.

3. Earth is the only planet with life and water.

4. Mars is the red planet, known for iron-rich soil.

5. Jupiter is the largest planet, a gas giant with many moons.

6. Saturn is famous for its beautiful rings.

7. Uranus is a gas planet that rotates on its side.

8. Neptune is a cold, blue gas planet, far from the Sun.

9. Pluto is once considered a planet, now classified as a dwarf planet.

Summary – The Solar System has 9 planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. The first four are rocky planets, the next four are gas giants, and Pluto is a dwarf planet.

 

GRAVITY AND THE WEIGHTLESSNESS IN THE SPACE

1. Gravity is the force that pulls objects toward the Earth or any other planet.

Key Points:

• It keeps us on the ground so we do not float away.

• It holds the Moon around the Earth and planets around the Sun.

• The heavier an object, the stronger the pull of gravity on it.

Example – When you drop a ball, it falls to the ground because of gravity.

 

2. Weightlessness in Space 

Weightlessness happens when there is very little or no gravity, like in space.

Key Points:

• Astronauts appear to float inside the space shuttle.

• Objects do not fall to the ground; they float freely.

• Weightlessness happens because the spacecraft and everything inside it are falling around the Earth together (orbiting).

Example – In the International Space Station (ISS), astronauts can float and perform experiments in a weightless environment.

 

Differences Between Gravity and Weightlessness

Gravity

1. Gravity pulls objects toward the Earth. While, Objects feel weightless.

2. Gravity keeps us on the ground. While, No noticeable pull, objects float.

3. Gravity makes objects have weight. While, Astronauts float in space.

Summary – Gravity is the force that pulls objects toward the Earth, while weightlessness is the condition in space where objects appear to float because there is very little or no gravity.

 

10 MULTIPLE CHOICE QUESTIONS AND ANSWERS ON SOLAR SYSTEM – NATURAL BODIES IN THE SKY | GRAVITY AND WEIGHTLESSNESS IN THE SPACE

INSTRUCTION – Choose the correct answer from the options A – D. 

1. The Solar System is made up of ______. 

A. the Sun and objects that move around it

B. only planets

C. the Moon and stars only

D. only Earth and Moon

 

2. Which planet is closest to the Sun?

A. Venus

B. Mercury

C. Mars

D. Earth

 

3. Which planet is known as the Red Planet?

A. Mars

B. Jupiter

C. Venus

D. Saturn

 

4. Which planet is the largest in the Solar System?

A. Earth

B. Jupiter

C. Neptune

D. Mars

 

5. Pluto is classified as a ______. 

A. rocky planet

B. gas giant

C. dwarf planet

D. star

 

6. The force that pulls objects toward the Earth is called ______. 

A. magnetism

B. gravity

C. weightlessness

D. friction

 

7. Weightlessness in space occurs because ______. 

A. there is no Sun

B. objects are very light

C. Earth is spinning

D. there is very little or no gravity

 

8. Which of the following is a gas giant?

A. Mercury

B. Mars

C. Saturn

D. Venus

 

9. The planets that are small and made of rock are ______. 

A. Mercury, Venus, Earth, Mars

B. Jupiter, Saturn, Uranus, Neptune

C. Mars, Jupiter, Saturn, Uranus

D. Venus, Saturn, Pluto, Earth

 

10. Astronauts float in space because ______. 

A. there is no air

B. there is no gravity

C. they are too heavy

D. they move too fast

 

FILL IN THE GAP QUESTIONS

11. The Solar System is made up of the Sun and the ______ that move around it.

12. There are ______ planets in the Solar System according to the old classification.

13. The force that pulls objects toward the Earth is called ______.

14. Jupiter, Saturn, Uranus, and Neptune are known as ______ planets.

15. Astronauts float in space because of ______.

 

SHORT ANSWER QUESTIONS

16. What is the Solar System?

17. Name the first four planets from the Sun.

18. What is gravity?

19. What is weightlessness?

20. Mention one importance of gravity on Earth.

 

ANSWER KEYS

1. A 2. B 3. A 4. B 5. C 6. B 7. D 8. C 9. A 10. B 11. planets 12. nine 13. gravity 14. gas giant 15. weightlessness

16. The Solar System is made up of the Sun and all the objects that move around it.

17. Mercury, Venus, Earth, and Mars.

18. Gravity is the force that pulls objects toward the Earth or any planet.

19. Weightlessness is the condition in space where objects appear to float because there is very little gravity.

20. Gravity keeps us on the ground and prevents us from floating away.