Lesson Notes By Weeks and Term v5 - Grade 6

Lesson Video

This page supports the lesson note with a companion video and a short classroom-ready summary.

For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.

Performance objectives

• Identify and describe the characteristics of the inner and outer planets.
• Compare the sizes of the planets relative to each other and the Sun.
• Explain the concept of a planet's orbit.
• Describe the role of the Sun as the central star.

Lesson summary

The Solar System is more than just a beautiful picture in a book. It's our neighbourhood in the vast universe, and understanding it helps us appreciate our place in the cosmos. Learning about the planets, their characteristics, and how they move allows us to understand day and night, seasons, and even how technology like satellites that bring us DSTV and help us communicate are placed and function. As South Africans, it is vital to understand these concepts because they are the foundation for future careers in science, technology, engineering, and mathematics (STEM) fields.

Lesson notes

The Solar System consists of the Sun and all the objects that orbit it: planets, moons, asteroids, and comets. These objects are held together by gravity. The Sun, a giant star, is at the centre of it all, providing light and heat to the planets. Let's explore the planets.

They are divided into two main groups: inner planets and outer planets.

Inner Planets (Terrestrial Planets): These planets are closer to the Sun, smaller, rocky, and have few or no moons.

Mercury: The smallest planet and closest to the Sun. It has a very thin atmosphere and extreme temperature variations. Imagine a hot day in the Karoo but much, much hotter, and then a freezing night. Mercury has almost no atmosphere to trap heat.

Venus: Similar in size to Earth, Venus is incredibly hot and has a thick, toxic atmosphere. The atmosphere is almost entirely carbon dioxide, trapping heat and creating a runaway greenhouse effect. Its surface is covered in volcanoes and lava flows.

Earth: Our home! It is the only planet known to support life, with liquid water, a breathable atmosphere, and a stable temperature. Earth has one moon.

Mars: Known as the "Red Planet" due to its iron-rich soil. Mars has a thin atmosphere, polar ice caps, and evidence of past liquid water. Scientists are exploring Mars for signs of past or present life.

Outer Planets (Gas Giants): These planets are farther from the Sun, larger, mostly made of gas, and have many moons and rings.

Jupiter: The largest planet in the Solar System. It is made mostly of hydrogen and helium and has a giant storm called the Great Red Spot that has been raging for hundreds of years. Jupiter has many moons, including the four largest called the Galilean moons.

Saturn: Famous for its spectacular rings, which are made of ice and rock particles. Saturn is also a gas giant and has many moons.

Uranus: A gas giant that rotates on its side. It has a faint ring system and many moons. Uranus is very cold.

Neptune: The farthest planet from the Sun. It is a gas giant with a dark blue colour and strong winds. Neptune also has rings and moons.

Planet Sizes: Understanding relative size is crucial. Think of the Sun as a big watermelon.

Then: Jupiter would be about the size of a tennis ball. Saturn would be slightly smaller than a tennis ball. Uranus and Neptune would be around the size of oranges. Earth and Venus would be about the size of grapes. Mars would be the size of a blueberry. Mercury would be about the size of a peppercorn.

Planet Orbits: Each planet travels around the Sun in a specific path called an orbit. These orbits are elliptical (oval-shaped), not perfect circles. The time it takes for a planet to complete one orbit is called its orbital period or year. Planets closer to the Sun orbit faster because the Sun's gravitational pull is stronger.