Unit Plan 7 (Grade 6 Science): Stars, Galaxies & the Universe
Grade 6 unit where students analyze star brightness and distance, model the Milky Way’s structure and gravity, and explore our place in the universe.
Focus: Interpret data on star brightness and distance and use models to describe the structure of the Milky Way galaxy, the role of gravity in keeping stars and systems in orbit, and the scale of our place in the universe.
Grade Level: 6
Subject Area: Science (Earth & Space Science — Space Systems • Scale & Gravity)
Total Unit Duration: 5 sessions (one week), 50–60 minutes per session
I. Introduction
In this unit, students zoom out beyond the solar system to explore stars, galaxies, and the universe. They analyze simple data tables for star brightness and distance, noticing patterns in why some stars appear bright (because they are close, intrinsically luminous, or both). They use diagrams and models to describe the Milky Way’s structure as a disk-shaped galaxy with spiral arms, and identify where our solar system sits within it. Students connect MS-ESS1-2 ideas about gravity and orbital motion to stars orbiting the galactic center, and extend MS-ESS1-3 thinking about scale from the solar system to the much larger scales of galaxies and the universe.
Essential Questions
- Why do some stars look brighter than others when we see them from Earth?
- What does our data tell us about the distance to different stars and their true brightness?
- What is the Milky Way galaxy, and where is our solar system located within it?
- How does gravity act on stars and systems within a galaxy, and how is this similar to and different from gravity in the solar system?
- How can models and scale comparisons help us imagine our place in the universe?
II. Objectives and Standards
Learning Objectives — Students will be able to:
- Analyze and interpret data tables showing star apparent brightness and distance, explaining why some stars appear brighter in the night sky than others.
- Distinguish between apparent brightness (how bright a star looks from Earth) and distance, and describe how each affects what we see.
- Develop and use models of the Milky Way galaxy to show its disk shape, spiral arms, and the approximate location of our solar system.
- Explain qualitatively how gravity holds stars in orbit around the galactic center, connecting this to prior models of gravity and orbits in the solar system.
- Use scale comparisons (e.g., solar system vs. galaxy vs. observable universe) to describe the relative sizes and distances involved, and critique the strengths and limitations of common pictures and models.
Standards Alignment — 6th Grade (NGSS-based custom)
- MS-ESS1-2 — Develop and use a model to describe the role of gravity in the motion of objects within space systems.
- In this unit: students extend from the solar system to model how gravity holds stars and star systems in orbit around the center of the Milky Way.
- MS-ESS1-3 — Analyze and interpret data to determine scale properties of objects in the solar system.
- In this unit: students apply similar data and scale reasoning to stars and galaxies, using star data and size/distance comparisons to extend their understanding of scale beyond the solar system.
Success Criteria — Student Language
- I can read a star data table and explain why one star looks brighter than another (closer, more luminous, or both).
- I can describe the shape of the Milky Way and show about where our solar system is in it.
- I can explain that gravity pulls stars toward the galactic center and keeps them in orbit, similar to how the Sun pulls planets.
- I can use scale comparisons (like “solar system vs. galaxy”) to explain how big space is.
- I can point out one strength and one limitation of a picture or model of the galaxy or universe.