Science · 6th Grade · Earth's Place in the Universe · Quarter 4

A Tour of the Solar System

Journey through our solar system to learn about the Sun, planets, moons, asteroids, and comets that are all held together by the force of gravity.

TL;DR:Take your students on an interplanetary journey to explore the wonders of our solar system. This topic moves beyond memorization to build a conceptual model of our cosmic home.

• Common Core State Standards
• NGSS: MS-ESS1 - Earth's Place in the Universe

About This Topic

This topic, 'A Tour of the Solar System,' aligns with the Next Generation Science Standards (NGSS) for middle school, particularly within the Earth and Space Sciences domain (MS-ESS1-2 and MS-ESS1-3). The core of this unit is developing a systems-level understanding of the solar system. Students will move beyond simply naming the planets to analyzing patterns in their characteristics, such as composition, size, and distance from the Sun. The central organizing principle is the force of gravity, which students will learn is responsible for the formation of the Sun and planets, the orbital paths of celestial bodies, and the overall structure of the solar system.

The curriculum encourages the use of models to grapple with the immense scale of space, a concept that is often abstract for sixth graders. By comparing the terrestrial inner planets to the gas giants of the outer solar system, students practice classification and data analysis. The topic also broadens their perspective to include other significant components like the asteroid belt, Kuiper Belt, comets, and moons, painting a more complete and dynamic picture of our cosmic neighborhood. The goal is to foster an appreciation for the predictable, physics-based patterns that govern our solar system and to lay the groundwork for more complex astronomical concepts in later grades.

Key Questions

1. Compare the characteristics of the inner, rocky planets with the outer, gas giant planets.
2. Explain the role of gravity in forming and maintaining the structure of the solar system.
3. Identify the key components of our solar system beyond the planets, such as asteroids and comets.

Learning Objectives

• Compare and contrast the physical properties of the inner terrestrial planets and the outer gas giants.
• Develop and use a model to explain the role of gravity in governing the motions of objects within the solar system.
• Identify and describe the major components of the solar system, including the Sun, planets, moons, asteroids, and comets.
• Analyze data about planetary characteristics to identify patterns and relationships.

Key Vocabulary

Solar System	The collection of the Sun and all the celestial bodies that are held in its gravitational field, including planets, moons, asteroids, comets, and dwarf planets.
Gravity	The universal force of attraction acting between all matter. It is the force that keeps the planets in orbit around the Sun.
Orbit	The curved path of a celestial object or spacecraft around a star, planet, or moon, especially a periodic elliptical revolution.
Planet	A celestial body moving in an elliptical orbit around a star, which has cleared its orbital neighborhood of other objects.
Asteroid	A small, rocky body orbiting the Sun, with most found in the asteroid belt between Mars and Jupiter.
Comet	A celestial object consisting of a nucleus of ice and dust and, when near the Sun, a 'tail' of gas and dust particles pointing away from the Sun.

Watch Out for These Misconceptions

Common Misconception

The asteroid belt is a crowded, dense field of rocks that is difficult to fly through.

What to Teach Instead

The asteroid belt is vast, and the asteroids within it are very far apart. Spacecraft have flown through it many times without any issue, as the average distance between large asteroids is hundreds of thousands of miles.

Common Misconception

Planets, moons, and stars are all the same type of object.

What to Teach Instead

Stars, like our Sun, produce their own light through nuclear fusion. Planets and moons do not produce their own light; they are visible because they reflect the light from a star they orbit.

Common Misconception

Gravity is a force that only exists on Earth, or it 'turns off' in space.

What to Teach Instead

Gravity is a universal force of attraction between any two objects with mass. Astronauts on the International Space Station appear weightless because they are in a constant state of freefall, orbiting Earth, not because there is no gravity.

Common Misconception

The orbits of planets are perfect circles.

What to Teach Instead

Planetary orbits are not perfect circles but are slightly oval-shaped paths called ellipses. The Sun is not at the exact center but at one of the two focal points of the ellipse.

Active Learning Ideas

Jigsaw

Pocket Solar System

Students create a scale model of the distances between planets using a long strip of register tape. They make a series of folds to represent the vast and unequal spacing of the planets' orbits, challenging their perception of a uniformly spaced system.

45 min·Individual

Jigsaw

Planet Travel Agency

In small groups, students research a specific planet or moon and create a travel brochure or digital presentation to attract tourists. They must include key facts like temperature, gravity, atmospheric conditions, and unique features, creatively highlighting both the attractions and the dangers.

90 min·Small Groups

Jigsaw

Gravity Well Demonstration

Stretch a large piece of spandex or fabric over a hoop to create a 'gravity well.' Students roll marbles of different masses across the fabric to visualize how larger objects (like the Sun) warp spacetime and cause smaller objects (like planets) to orbit.

30 min·Whole Class

Real-World Connections

• Satellite communication and GPS navigation depend on precise calculations of orbits and gravitational forces.
• Understanding the Sun's activity helps predict space weather, which can affect power grids and communication systems on Earth.
• Studying asteroids and comets helps scientists understand the formation of the solar system and assess potential impact risks to Earth.
• The engineering of spacecraft and probes for planetary exploration requires a deep understanding of gravity, orbits, and the conditions on other worlds.
• Knowledge of planetary orbits and Earth's rotation explains natural phenomena like seasons, tides, and the day-night cycle.

Assessment Ideas

Exit Ticket

Use an exit ticket where students must list two characteristics of an inner planet and two of an outer planet to check for understanding of key differences.

Peer Assessment

Students create a scaled model or a digital presentation of the solar system, correctly labeling all planets and other key features like the asteroid belt, and providing a brief explanation of gravity's role.

Quick Check

Provide students with a checklist of the learning objectives and key vocabulary terms, allowing them to rate their confidence level (e.g., 'I can teach this,' 'I understand,' 'I need help').

Frequently Asked Questions

Why isn't Pluto considered a planet anymore?

In 2006, the International Astronomical Union defined a planet as a celestial body that orbits the Sun, is massive enough to be rounded by its own gravity, and has 'cleared its neighborhood' of other objects. Pluto meets the first two criteria but not the third, as its orbit is full of other objects in the Kuiper Belt. It is now classified as a 'dwarf planet.'

What is the difference between an asteroid, a comet, and a meteor?

Asteroids are rocky, metallic objects that mostly orbit the Sun in the asteroid belt. Comets are made of ice, dust, and rock, and they develop a glowing tail as they get closer to the Sun. A meteoroid is a small piece of an asteroid or comet, which becomes a meteor (or 'shooting star') when it burns up in Earth's atmosphere, and a meteorite if it survives to hit the ground.

How does the Sun produce so much heat and light?

The Sun produces energy through a process called nuclear fusion in its core. Under immense pressure and temperature, hydrogen atoms fuse together to form helium, releasing a tremendous amount of energy in the form of light and heat.