Planets of Our Solar System

Active learning helps students grasp the vast scale of our solar system and the unique properties of each planet. By engaging with simulations and investigations, students move beyond memorizing names to understanding relationships between planets and their features.

• 6th Class
• Scientific Inquiry and the Natural World
• 3 activities
• 25 min–45 min

Learning Objectives

1. Compare the inner and outer planets of our solar system based on their composition, size, and distance from the Sun.
2. Analyze the unique characteristics and atmospheric conditions of each planet.
3. Explain the criteria used by astronomers to classify celestial bodies as planets, justifying Pluto's reclassification.
4. Identify the key features of dwarf planets and other objects in the solar system.

Inquiry Circle

⏱ 45 min·Small Groups

Inquiry Circle: The Solar Still

Groups create a 'solar still' using a bowl, a cup, and plastic wrap. They place 'dirty' salty water in the bowl and leave it in the sun. They must observe how evaporation and condensation produce clean, fresh water in the cup, mimicking the natural cycle.

Prepare & details

Compare the inner and outer planets based on their composition and size.

Facilitation Tip: During The Solar Still, circulate to ensure groups measure condensation carefully and discuss why it forms on the lid.

Setup: Groups at tables with access to source materials

Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Simulation Game

⏱ 30 min·Individual

Simulation Game: The Water Drop Journey

Students act as water molecules and move between stations (Ocean, Cloud, River, Glacier) based on the roll of a die. They keep a 'travel diary' of their changes in state, helping them realize that the cycle isn't just a simple circle but a complex web.

Prepare & details

Analyze the unique features of each planet.

Facilitation Tip: In The Water Drop Journey, provide each student with a colored pencil to trace their drop’s path on a shared poster for visual tracking.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Formal Debate

⏱ 25 min·Small Groups

Formal Debate: The Puddle Mystery

The teacher presents a photo of a puddle that disappeared. Students must debate where the water went, using scientific terms like 'evaporation' and 'vapor,' and provide evidence for why it didn't just 'soak away' if the ground was concrete.

Prepare & details

Justify why Pluto is no longer classified as a planet.

Facilitation Tip: For The Puddle Mystery, assign roles to students to keep the debate structured and time-box each speaker’s contribution.

Setup: Two teams facing each other, audience seating for the rest

Materials: Debate proposition card, Research brief for each side, Judging rubric for audience, Timer

• Analyze
• Evaluate
• Create
• Self-Management
• Decision-Making

Teaching This Topic

Experienced teachers build models to scale, using relative distances and sizes to make abstract concepts concrete. They avoid overwhelming students with too many details at once and instead focus on patterns, such as the division between rocky and gas planets. Research suggests pairing visuals with hands-on investigations deepens retention more than lectures alone.

What to Expect

Successful learning looks like students confidently identifying the eight planets, explaining their key characteristics, and justifying classifications based on clear criteria. They should also compare planets meaningfully and discuss the reasons behind planetary reclassifications.

Watch Out for These Misconceptions

Common Misconception

During The Solar Still, watch for students believing water is lost or created during evaporation and condensation.

What to Teach Instead

Use the experiment to show the water’s mass remains constant by weighing the still before and after. Ask students to trace the water’s movement with arrows on a diagram of their still.

Common Misconception

During the Simulation: The Water Drop Journey, watch for students describing clouds as made of water vapor.

What to Teach Instead

Have students observe how the ‘water drop’ turns from invisible vapor to visible droplets in their simulation. Use a quick cloud-in-a-bottle demo to show condensation on the bottle’s sides.

Assessment Ideas

Quick Check

After Collaborative Investigation: The Solar Still, collect written responses where students explain why the water collected in the still despite not being added, using terms like evaporation and condensation.

Discussion Prompt

During Structured Debate: The Puddle Mystery, assess understanding by listening for students’ use of the term ‘dwarf planet’ and their reference to the three criteria from the IAU definition in their arguments.

Exit Ticket

After Simulation: The Water Drop Journey, have students label a blank solar system diagram with the names of two planets and one unique feature for each, explaining how those features relate to their classification.

Extensions & Scaffolding

• Challenge: Ask students to research and present on one of the dwarf planets, explaining why it does not meet full planet criteria.
• Scaffolding: Provide a word bank with key terms (e.g., orbit, atmosphere, gravity) and sentence starters for describing planets.
• Deeper exploration: Have students calculate the relative sizes of planets using simple ratios and compare their findings to NASA data.

Key Vocabulary

Terrestrial Planets	The four inner planets (Mercury, Venus, Earth, Mars) that are primarily composed of rock and metal, with solid surfaces.
Gas Giants	The four outer planets (Jupiter, Saturn, Uranus, Neptune) that are much larger than terrestrial planets and composed mainly of hydrogen and helium.
Dwarf Planet	A celestial body that orbits the Sun, is massive enough for its gravity to make it nearly round, but has not cleared its orbital neighborhood of other objects.
Astronomical Unit (AU)	A unit of length used to measure distances in the solar system, equal to the average distance between the Earth and the Sun (about 150 million kilometers).