Galaxies: Islands of Stars (Part 4)

What You'll Learn

Galaxies are enormous collections of stars, gas, and dust held together by gravity. Our Milky Way galaxy contains hundreds of billions of stars and is a spiral galaxy.

Key Words

inner planets
outer planets
atmosphere

Steps

Step 1 — Read

Read the introduction and identify the main idea of this lesson.

Step 2 — Do

Build a scale model of the inner solar system using different-sized balls. Research the relative sizes and distances of the planets.

Step 3 — Observe

Observe what happens and describe it in detail.

Step 4 — Record

Record your observations in your science journal with measurements and descriptions.

Check Your Understanding

Question 1

1 of 3

What is a galaxy?